diff --git a/app/django/timetables/management/commands/exportcsv.py b/app/django/timetables/management/commands/exportcsv.py
index 7658109..13996ce 100644
--- a/app/django/timetables/management/commands/exportcsv.py
+++ b/app/django/timetables/management/commands/exportcsv.py
@@ -5,6 +5,7 @@
 import csv
 import sys
 import argparse
+import collections
 
 import pytz
 
@@ -84,15 +85,17 @@ def export_to_csv_writer(self, csv_writer):
 
         for event in self.events:
             try:
-                self.write_row(csv_writer, self.get_row(event))
+                for event_path in paths_to(event):
+                    self.write_row(csv_writer, self.get_row(event_path))
             except InvalidStructureException as e:
                 print >> sys.stderr, "Skipping event", event.pk, e
 
     def get_header_row(self):
         return [spec.get_column_name() for spec in self.columns]
 
-    def get_row(self, event):
-        return [spec.extract_value(event) for spec in self.columns]
+    def get_row(self, event_path):
+        assert isinstance(event_path, EventPath)
+        return [spec.extract_value(event_path) for spec in self.columns]
 
     def write_row(self, csv_writer, row):
         for f in self.filters:
@@ -101,6 +104,43 @@ def write_row(self, csv_writer, row):
         csv_writer.writerow(row)
 
 
+
+EventPath = collections.namedtuple(
+    "EventPath", "tripos part subpart module series event".split())
+
+
+def paths_to(event):
+    """
+    Get the possible paths through the Thing tree to an Event
+
+    An iterable of EventPaths is returned representing each way
+    an Event can be reached from the root. There's usually a single
+    path, but when a series is linked to more than one module an Event
+    in the series will have > 1 way to access it from the root.
+    """
+    series_traverser = EventTraverser(event).step_up()
+    for module_traverser in series_traverser.walk_parents():
+        mod_parent_traverser = module_traverser.step_up()
+
+        if mod_parent_traverser.name == SubpartTraverser.name:
+            subpart = mod_parent_traverser.get_value()
+            part_traverser = mod_parent_traverser.step_up()
+        else:
+            subpart = None
+            assert mod_parent_traverser.name == PartTraverser.name
+            part_traverser = mod_parent_traverser
+
+        tripos_traverser = part_traverser.step_up()
+
+        yield EventPath(
+            tripos_traverser.get_value(),
+            part_traverser.get_value(),
+            subpart,
+            module_traverser.get_value(),
+            series_traverser.get_value(),
+            event)
+
+
 class UnicodeEncodeRowFilter(object):
     encoding = "utf-8"
 
@@ -125,109 +165,97 @@ def __init__(self, name=None):
     def get_column_name(self):
         return self.name
 
-    def extract_value(self, event):
+    def extract_value(self, event_path):
         raise NotImplementedError()
 
-    def get_series(self, event):
-        return EventTraverser(event).step_up().get_value()
-
-    def get_module(self, event):
-        series = self.get_series(event)
-        return SeriesTraverser(series).step_up().get_value()
+    def get_event(self, event_path):
+        return event_path.event
 
-    def get_subpart(self, event):
-        module = self.get_module(event)
-        traverser = ModuleTraverser(module).step_up()
+    def get_series(self, event_path):
+        return event_path.series
 
-        if traverser.name == SubpartTraverser.name:
-            return traverser.get_value()
-        return None
+    def get_module(self, event_path):
+        return event_path.module
 
-    def get_part(self, event):
-        subpart = self.get_subpart(event)
-        if subpart is not None:
-            traverser = SubpartTraverser(subpart)
-        else:
-            traverser = ModuleTraverser(self.get_module(event))
+    def get_subpart(self, event_path):
+        return event_path.subpart
 
-        part_traverser = traverser.step_up()
-        assert part_traverser.name == PartTraverser.name
-        return part_traverser.get_value()
+    def get_part(self, event_path):
+        return event_path.part
 
-    def get_tripos(self, event):
-        part = self.get_part(event)
-        return PartTraverser(part).step_up().get_value()
+    def get_tripos(self, event_path):
+        return event_path.tripos
 
 
 class TriposNameColumnSpec(ColumnSpec):
     name = "Tripos Name"
 
-    def extract_value(self, event):
-        tripos = self.get_tripos(event)
+    def extract_value(self, event_path):
+        tripos = self.get_tripos(event_path)
         return tripos.fullname
 
 
 class TriposShortNameColumnSpec(ColumnSpec):
     name = "Tripos Short Name"
 
-    def extract_value(self, event):
-        tripos = self.get_tripos(event)
+    def extract_value(self, event_path):
+        tripos = self.get_tripos(event_path)
         return tripos.name
 
 
 class PartNameColumnSpec(ColumnSpec):
     name = "Part Name"
 
-    def extract_value(self, event):
-        part = self.get_part(event)
+    def extract_value(self, event_path):
+        part = self.get_part(event_path)
         return part.fullname
 
 
 class PartShortNameColumnSpec(ColumnSpec):
     name = "Part Short Name"
 
-    def extract_value(self, event):
-        part = self.get_part(event)
+    def extract_value(self, event_path):
+        part = self.get_part(event_path)
         return part.name
 
 
 class SubPartNameColumnSpec(ColumnSpec):
     name = "Subpart Name"
 
-    def extract_value(self, event):
-        subpart = self.get_subpart(event)
+    def extract_value(self, event_path):
+        subpart = self.get_subpart(event_path)
         return None if subpart is None else subpart.fullname
 
 
 class SubPartShortNameColumnSpec(ColumnSpec):
     name = "Subpart Short Name"
 
-    def extract_value(self, event):
-        subpart = self.get_subpart(event)
+    def extract_value(self, event_path):
+        subpart = self.get_subpart(event_path)
         return None if subpart is None else subpart.name
 
 
 class ModuleNameColumnSpec(ColumnSpec):
     name = "Module Name"
 
-    def extract_value(self, event):
-        module = self.get_module(event)
+    def extract_value(self, event_path):
+        module = self.get_module(event_path)
         return module.fullname
 
 
 class ModuleShortNameColumnSpec(ColumnSpec):
     name = "Module Short Name"
 
-    def extract_value(self, event):
-        module = self.get_module(event)
+    def extract_value(self, event_path):
+        module = self.get_module(event_path)
         return module.name
 
 
 class SeriesNameColumnSpec(ColumnSpec):
     name = "Series Name"
 
-    def extract_value(self, event):
-        series = self.get_series(event)
+    def extract_value(self, event_path):
+        series = self.get_series(event_path)
         return series.title
 
 
@@ -238,8 +266,8 @@ def get_attr_name(self):
         assert self.attr_name is not None
         return self.attr_name
 
-    def extract_value(self, event):
-        return getattr(event, self.get_attr_name())
+    def extract_value(self, event_path):
+        return getattr(self.get_event(event_path), self.get_attr_name())
 
 
 class EventTitleColumnSpec(EventAttrColumnSpec):
@@ -255,8 +283,8 @@ class EventLocationColumnSpec(EventAttrColumnSpec):
 class EventUidColumnSpec(ColumnSpec):
     name = "UID"
 
-    def extract_value(self, event):
-        return event.get_ical_uid()
+    def extract_value(self, event_path):
+        return self.get_event(event_path).get_ical_uid()
 
 
 class EventDateTimeColumnSpec(ColumnSpec):
@@ -265,8 +293,8 @@ class EventDateTimeColumnSpec(ColumnSpec):
     def get_datetime_utc(self, event):
         raise NotImplementedError()
 
-    def extract_value(self, event):
-        dt_utc = self.get_datetime_utc(event)
+    def extract_value(self, event_path):
+        dt_utc = self.get_datetime_utc(self.get_event(event_path))
         return self.timezone.normalize(dt_utc.astimezone(self.timezone)).isoformat()
 
 
@@ -292,8 +320,8 @@ def get_metadata_path(self):
             raise ValueError("no metadata_path value provided")
         return self.metadata_path
 
-    def extract_value(self, event):
-        metadata = event.metadata
+    def extract_value(self, event_path):
+        metadata = self.get_event(event_path).metadata
 
         segments = self.get_metadata_path().split(".")
         for i, segment in enumerate(segments):
@@ -313,6 +341,6 @@ class EventLecturerColumnSpec(EventMetadataColumnSpec):
     name = "People"
     metadata_path = "people"
 
-    def extract_value(self, event):
-        value = super(EventLecturerColumnSpec, self).extract_value(event)
+    def extract_value(self, event_path):
+        value = super(EventLecturerColumnSpec, self).extract_value(event_path)
         return None if value is None else ", ".join(value)
diff --git a/app/django/timetables/management/commands/grasshopper_export_data.py b/app/django/timetables/management/commands/grasshopper_export_data.py
new file mode 100644
index 0000000..1ac7549
--- /dev/null
+++ b/app/django/timetables/management/commands/grasshopper_export_data.py
@@ -0,0 +1,131 @@
+"""
+Copy this file to:
+    app/django/timetables/management/commands/grasshopper_export_data.py
+
+Change directory so your current working directory is:
+    app/django
+
+Execute:
+    python manage.py grasshopper_export_data > data_dump.csv
+
+Depending on your machine, this can take a couple of minutes. You should end up with a CSV file
+that contains all the necessary data for each event to build up a tree.
+
+
+Export all events in the system into CSV format. Events with dodgy
+ancestors (invalid data) are skipped.
+"""
+import csv
+import sys
+import argparse
+
+from timetables.management.commands import exportcsv
+
+
+class Command(exportcsv.Command):
+
+    def __init__(self):
+        super(exportcsv.Command, self).__init__()
+
+        self.parser = argparse.ArgumentParser(
+            prog="grasshopper_export_events",
+            description=__doc__,
+            formatter_class=argparse.ArgumentDefaultsHelpFormatter
+        )
+
+    def handle(self, args):
+        events = self.get_events()
+
+        exporter = CsvExporter(
+            self.get_columns(),
+            [StripNewlinesRowFilter(), exportcsv.UnicodeEncodeRowFilter()],
+            events
+        )
+
+        exporter.export_to_stream(sys.stdout)
+
+    def get_columns(self):
+        return [
+            TriposIdColumnSpec(), exportcsv.TriposNameColumnSpec(),
+            PartIdColumnSpec(), exportcsv.PartNameColumnSpec(),
+            SubPartIdColumnSpec(), exportcsv.SubPartNameColumnSpec(),
+            ModuleIdColumnSpec(), exportcsv.ModuleNameColumnSpec(),
+            SeriesIdColumnSpec(), exportcsv.SeriesNameColumnSpec(),
+            EventIdColumnSpec(), exportcsv.EventTitleColumnSpec(),
+            exportcsv.EventTypeColumnSpec(),
+            exportcsv.EventStartDateTimeColumnSpec(),
+            exportcsv.EventEndDateTimeColumnSpec(),
+            exportcsv.EventLocationColumnSpec(),
+            EventLecturerColumnSpec()
+        ]
+
+
+class CsvExporter(exportcsv.CsvExporter):
+
+    def export_to_stream(self, dest):
+        csv_writer = csv.writer(dest, delimiter=',', quotechar='"', quoting=csv.QUOTE_ALL)
+        return self.export_to_csv_writer(csv_writer)
+
+
+class StripNewlinesRowFilter(object):
+    def strip_newlines(self, val):
+        if isinstance(val, basestring):
+            return val.replace("\n", "")
+        return val
+
+    def filter(self, row):
+        return [self.strip_newlines(val) for val in row]
+
+
+class TriposIdColumnSpec(exportcsv.ColumnSpec):
+    name = "Tripos Id"
+
+    def extract_value(self, event_path):
+        tripos = self.get_tripos(event_path)
+        return tripos.id
+
+
+class PartIdColumnSpec(exportcsv.ColumnSpec):
+    name = "Part Id"
+
+    def extract_value(self, event_path):
+        part = self.get_part(event_path)
+        return part.id
+
+
+class SubPartIdColumnSpec(exportcsv.ColumnSpec):
+    name = "Subpart Id"
+
+    def extract_value(self, event_path):
+        subpart = self.get_subpart(event_path)
+        return None if subpart is None else subpart.id
+
+
+class ModuleIdColumnSpec(exportcsv.ColumnSpec):
+    name = "Module Id"
+
+    def extract_value(self, event_path):
+        module = self.get_module(event_path)
+        return module.id
+
+
+class SeriesIdColumnSpec(exportcsv.ColumnSpec):
+    name = "Series ID"
+
+    def extract_value(self, event_path):
+        series = self.get_series(event_path)
+        return series.id
+
+
+class EventIdColumnSpec(exportcsv.EventAttrColumnSpec):
+    name = "Event ID"
+    attr_name = "id"
+
+
+class EventLecturerColumnSpec(exportcsv.EventMetadataColumnSpec):
+    name = "People"
+    metadata_path = "people"
+
+    def extract_value(self, event):
+        value = super(EventLecturerColumnSpec, self).extract_value(event)
+        return None if value is None else "#".join(value)
diff --git a/app/django/timetables/management/commands/grasshopper_export_structure.py b/app/django/timetables/management/commands/grasshopper_export_structure.py
new file mode 100644
index 0000000..40e9ddc
--- /dev/null
+++ b/app/django/timetables/management/commands/grasshopper_export_structure.py
@@ -0,0 +1,110 @@
+"""
+Copy this file to:
+    app/django/timetables/management/commands/grasshopper_export_structure.py
+
+Change directory so your current working directory is:
+    app/django
+
+Execute:
+    python manage.py grasshopper_export_structure > external-tree.json
+
+
+Export the triposes, parts and subjects to a tree. The tree follows the same structure as GrassHopper's
+import tree. i.e.,
+
+- Course
+  - Subject (optional)
+    - Part
+
+The parts will also contain the external_url data object
+"""
+import csv
+import sys
+import argparse
+import json
+
+import pytz
+
+from collections import defaultdict
+
+from timetables.models import Thing, Subjects
+from timetables.utils import manage_commands
+
+
+class Command(manage_commands.ArgparseBaseCommand):
+
+    def __init__(self):
+        super(Command, self).__init__()
+
+        self.parser = argparse.ArgumentParser(
+            prog="grasshopper_export_structure",
+            description=__doc__,
+            formatter_class=argparse.ArgumentDefaultsHelpFormatter
+        )
+
+    def handle(self, args):
+        # Get the tree
+        tree = self.get_tree()
+
+        # Print the tree
+        print json.dumps(tree, indent=4)
+
+    def get_tree(self):
+
+        root = {
+            'id': 0,
+            'name': 'Timetable',
+            'type': 'root',
+            'nodes': {}
+        }
+
+        for item in Subjects.all_subjects():
+            tripos = item.get_tripos()
+            part = item.get_part()
+            subject = item.get_most_significant_thing()
+
+
+            partData = None
+            if part.data:
+                partData = json.loads(part.data)
+                if partData['external_website_url']:
+                    partData['external'] = partData['external_website_url']
+                    del partData['external_website_url']
+
+
+            # Add the tripos/course into the tree
+            if tripos.id not in root['nodes']:
+                root['nodes'][tripos.id] = {
+                    'id': tripos.id,
+                    'name': tripos.fullname,
+                    'type': 'course',
+                    'nodes': {}
+                }
+
+            # If we're dealing with a subject, add it in
+            if subject.id != part.id:
+                if subject.id not in root['nodes'][tripos.id]['nodes']:
+                    root['nodes'][tripos.id]['nodes'][subject.id] = {
+                        'id': subject.id,
+                        'name': subject.fullname,
+                        'type': 'subject',
+                        'nodes': {}
+                    }
+
+                root['nodes'][tripos.id]['nodes'][subject.id]['nodes'][part.id] = {
+                    'id': part.id,
+                    'name': part.fullname,
+                    'data': partData,
+                    'type': 'part',
+                    'nodes': {}
+                }
+            else:
+                root['nodes'][tripos.id]['nodes'][part.id] = {
+                    'id': part.id,
+                    'name': part.fullname,
+                    'data': partData,
+                    'type': 'part',
+                    'nodes': {}
+                }
+
+        return root
diff --git a/app/django/timetables/management/commands/rollover_testcases.py b/app/django/timetables/management/commands/rollover_testcases.py
new file mode 100644
index 0000000..8af22e7
--- /dev/null
+++ b/app/django/timetables/management/commands/rollover_testcases.py
@@ -0,0 +1,115 @@
+"""
+Generate testcases to test event rollover from one academic year to another.
+"""
+from __future__ import unicode_literals
+
+import sys
+import json
+import argparse
+import itertools
+from datetime import time, datetime
+from collections import OrderedDict
+
+import pytz
+
+from timetables.utils import manage_commands
+from timetables.utils.academicyear import (TERM_MICHAELMAS, TERM_LENT,
+                                           TERM_EASTER, TERM_STARTS)
+from timetables.utils.datetimes import termweek_to_date, DAYS_REVERSE
+
+
+class Command(manage_commands.ArgparseBaseCommand):
+
+    def __init__(self):
+        super(Command, self).__init__()
+
+        self.parser = argparse.ArgumentParser(
+            prog="rollover_testcases",
+            description=__doc__,
+            formatter_class=argparse.ArgumentDefaultsHelpFormatter
+        )
+
+        self.parser.add_argument("years", metavar="YEAR", nargs="+",
+                                 type=get_academic_year)
+        self.parser.add_argument("--roll-timezone", type=get_timezone,
+                                 default="Europe/London", dest="roll_tz")
+        self.parser.add_argument("--report-timezone", type=get_timezone,
+                                 default="UTC", dest="report_tz")
+
+    def handle(self, args):
+        testcases = self.get_testcases(args.years, args.roll_tz,
+                                       args.report_tz)
+
+        output = OrderedDict([
+            ("roll_zone", args.roll_tz.zone),
+            ("years", args.years),
+            ("testcases", list(testcases))
+        ])
+
+        json.dump(output, sys.stdout, indent=4)
+
+    def get_testcases(self, years, roll_tz, report_tz):
+        assert len(years) > 0
+        for term, week, day, hour in self.get_term_instants():
+            minute = 0
+
+            testcase = OrderedDict([
+                ("academic", OrderedDict([
+                    ("term", term),
+                    ("week", week),
+                    ("day", day),
+                    ("hour", hour),
+                    ("minute", minute)
+                ]))
+            ])
+            testcase.update(
+                ("{:d}".format(year),
+                 self.get_timestamp(year, term, week, day, hour, minute,
+                                    roll_tz).astimezone(report_tz).isoformat())
+                for year in years
+            )
+
+            yield testcase
+
+    def get_timestamp(self, year, term, week, day, hour, minute, timezone):
+        """
+        Get the instant represented by a time, day and week in an academic term
+        as an aware datetime in the specified timezone.
+        """
+        date = termweek_to_date(year, term, week, day)
+        return timezone.localize(datetime.combine(date, time(hour, minute)))
+
+    def get_term_instants(self):
+        """
+        Generate the timestamps to include as test cases.
+
+        We produce one for each day of term (weeks 1-8 inclusive), plus 2 weeks
+        either side, so -1 to 10 inclusive.
+        """
+        terms = [TERM_MICHAELMAS, TERM_LENT, TERM_EASTER]
+        weeks = range(-1, 11)
+        # Days from Thurs, Fri ... Wed
+        days = [DAYS_REVERSE[(n + 3) % 7] for n in range(0, 7)]
+        hours = [0, 5, 10, 12, 15, 20]
+
+        return itertools.product(terms, weeks, days, hours)
+
+
+def get_academic_year(year):
+    try:
+        year = int(year)
+    except ValueError:
+        raise argparse.ArgumentTypeError("Invalid year: {}".format(year))
+
+    if year not in TERM_STARTS:
+        raise argparse.ArgumentTypeError("No term dates available for year: {}"
+                                         .format(year))
+    return year
+
+
+def get_timezone(zone_name):
+    try:
+        return pytz.timezone(zone_name)
+    except pytz.UnknownTimeZoneError:
+        raise argparse.ArgumentTypeError(
+            "Unknown timezone: {0}".format(zone_name))
diff --git a/app/django/timetables/utils/traversal.py b/app/django/timetables/utils/traversal.py
index 1f44e4b..fd309a2 100644
--- a/app/django/timetables/utils/traversal.py
+++ b/app/django/timetables/utils/traversal.py
@@ -26,8 +26,11 @@ def validate_obj(self):
         pass
 
     def step_up(self):
+        return self._step(self.get_parent())
+
+    def _step(self, parent):
         try:
-            traverser, parent = self.get_parent()
+            traverser, parent = parent
             return traverser(parent)
         except ValidationException as e:
             raise InvalidStructureException(
@@ -80,20 +83,30 @@ def validate_obj(self):
                 "Expected an EventSource instance", self.obj)
 
     def get_parent(self):
+        return next(self.get_parents())
+
+    def walk_parents(self):
+        """
+        Enumerate all traversers for all parent modules of the current series.
+        """
+        for parent in self.get_parents():
+            yield self._step(parent)
+
+    def get_parents(self):
         series = self.obj
-        tags = series.eventsourcetag_set.all()
+        tags = list(series.eventsourcetag_set.filter(annotation="home"))
 
-        try:
-            tag = next(tag for tag in tags if tag.annotation == "home")
-            module = tag.thing
-        except StopIteration:
-            raise ValidationException(
+        if(len(tags) == 0):
+            raise InvalidStructureException(
                 "Orphaned series with no module encountered", series.pk)
 
-        if module.type != "module":
-            raise ValidationException(
-                "Series attached to non-module thing", series.pk)
-        return (ModuleTraverser, module)
+        for tag in tags:
+            module = tag.thing
+
+            if module.type != "module":
+                raise InvalidStructureException(
+                    "Series attached to non-module thing", series.pk)
+            yield (ModuleTraverser, module)
 
 
 class ModuleTraverser(ThingTraverserMixin, Traverser):
diff --git a/fixtures/representative/README.md b/fixtures/representative/README.md
new file mode 100644
index 0000000..a0b7a2b
--- /dev/null
+++ b/fixtures/representative/README.md
@@ -0,0 +1,14 @@
+This directory contains a small dataset intended to be representative of all
+of the types of data encountered in Timetable.
+
+The ``django-fixture.json`` file was created using:
+
+    $ dj dumpdata --indent=4 --format=json -e timetables.ThingLock timetables
+
+``gh-data.csv`` was created by loading ``django-fixture.json`` into a clean Timetable install, then running:
+
+    $ dj grasshopper_export_data
+
+``gh-tree.json`` was created by running [``etc/scripts/timetable/old-stack-import/generate-tree.js``](https://github.com/fronteerio/grasshopper/blob/bd5741355509af84d2b374172579b17d83e72ac5/etc/scripts/timetable/old-stack-import/generate-tree.js) from the [grasshopper](https://github.com/fronteerio/grasshopper) repo on ``gh-data.csv``.
+
+The data in all 3 files has been manually verified to be mutually consistent.
diff --git a/fixtures/representative/django-fixture.json b/fixtures/representative/django-fixture.json
new file mode 100644
index 0000000..5f3ef9f
--- /dev/null
+++ b/fixtures/representative/django-fixture.json
@@ -0,0 +1,1086 @@
+[
+{
+    "pk": 1, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "tripos", 
+        "parent": null, 
+        "data": "", 
+        "pathid": "p4pmLBPvFQjdJGPWzPW-yahYfT0=", 
+        "fullpath": "tripos", 
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+    "fields": {
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+        "end": "2014-10-10T12:00:00Z", 
+        "versionstamp": "2015-05-22T20:34:31.606Z", 
+        "title": "D1", 
+        "source": 4, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-10-10T11:00:00Z", 
+        "master": 10, 
+        "location": "Room D", 
+        "uid": "efd977cd-eb72-42e5-8516-8f6883620f28", 
+        "data": "{\"type\": \"lecture\", \"people\": [\"Prof D\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 14, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2015-01-16T13:00:00Z", 
+        "versionstamp": "2015-05-22T20:34:31.625Z", 
+        "title": "D2", 
+        "source": 4, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2015-01-16T12:00:00Z", 
+        "master": 12, 
+        "location": "Room D", 
+        "uid": "77aadf4b-2a54-48f0-9d3b-3818471c95cf", 
+        "data": "{\"type\": \"lecture\", \"people\": [\"Prof D\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 15, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2015-04-24T12:00:00Z", 
+        "versionstamp": "2015-05-22T20:34:31.640Z", 
+        "title": "D3", 
+        "source": 4, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2015-04-24T11:00:00Z", 
+        "master": null, 
+        "location": "Room D", 
+        "uid": "634053a1-a29c-4ecc-aa42-61c836208857", 
+        "data": "{\"type\": \"lecture\", \"people\": [\"Prof D\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 16, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-09-25T09:00:00Z", 
+        "versionstamp": "2015-05-22T20:40:04.192Z", 
+        "title": "D2 Thing", 
+        "source": 5, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-09-25T08:00:00Z", 
+        "master": null, 
+        "location": "Room D", 
+        "uid": "2ee5f91e-9d3d-46fd-8bf6-f54a5bf15498", 
+        "data": "{\"type\": \"presentation\", \"people\": [\"Mr Pink\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 17, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-10-02T09:00:00Z", 
+        "versionstamp": "2015-05-22T20:40:04.211Z", 
+        "title": "D2 Thing", 
+        "source": 5, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-10-02T08:00:00Z", 
+        "master": null, 
+        "location": "Room D", 
+        "uid": "16b69975-be65-41d2-a12c-6c10fd072e27", 
+        "data": "{\"type\": \"presentation\", \"people\": [\"Mr Pink\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 18, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-12-04T10:00:00Z", 
+        "versionstamp": "2015-05-22T20:40:04.228Z", 
+        "title": "D2 Thing", 
+        "source": 5, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-12-04T09:00:00Z", 
+        "master": null, 
+        "location": "Room D", 
+        "uid": "2f3761e1-1205-4262-85ae-2e8a22044bc4", 
+        "data": "{\"type\": \"presentation\", \"people\": [\"Mr Pink\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 19, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-12-11T10:00:00Z", 
+        "versionstamp": "2015-05-22T20:40:04.243Z", 
+        "title": "D2 Thing", 
+        "source": 5, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-12-11T09:00:00Z", 
+        "master": null, 
+        "location": "Room D", 
+        "uid": "28874f98-8e5b-40a4-a64a-699010af7f70", 
+        "data": "{\"type\": \"presentation\", \"people\": [\"Mr Pink\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 20, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-10-14T14:00:00Z", 
+        "versionstamp": "2015-05-22T20:43:53.282Z", 
+        "title": "Event E", 
+        "source": 6, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-10-14T13:00:00Z", 
+        "master": null, 
+        "location": "Room E", 
+        "uid": "13764e88-afb0-4407-89fb-9924c9d108a9", 
+        "data": "{\"type\": \"class\", \"people\": [\"Ms E\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 21, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-11-07T09:00:00Z", 
+        "versionstamp": "2015-05-22T20:48:50.190Z", 
+        "title": "Event F", 
+        "source": 7, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-11-07T08:00:00Z", 
+        "master": null, 
+        "location": "Room F", 
+        "uid": "75367174-0791-4132-89bb-541e19d64ac4", 
+        "data": "{\"type\": \"seminar\", \"people\": [\"Mr F\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 22, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2015-02-09T14:00:00Z", 
+        "versionstamp": "2015-05-22T20:51:09.211Z", 
+        "title": "Event G", 
+        "source": 8, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2015-02-09T13:00:00Z", 
+        "master": null, 
+        "location": "Room G", 
+        "uid": "288e88be-9fa0-46e1-bb94-cbd8ce39dc3d", 
+        "data": "{\"type\": \"seminar\", \"people\": [\"Gee Gson\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 23, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-10-30T18:00:00Z", 
+        "versionstamp": "2015-05-22T20:52:59.525Z", 
+        "title": "Event H", 
+        "source": 9, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-10-30T17:00:00Z", 
+        "master": null, 
+        "location": "Room H", 
+        "uid": "9ae81002-5484-47ee-a54c-fffe5cf5b8c1", 
+        "data": "{\"type\": \"\", \"people\": [\"Dr H\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 24, 
+    "model": "timetables.event", 
+    "fields": {
+        "status": 0, 
+        "end": "2014-10-09T09:00:00Z", 
+        "versionstamp": "2015-05-22T21:13:41.890Z", 
+        "title": "Intro to Subject A", 
+        "source": 10, 
+        "endtz": "Europe/London", 
+        "current": true, 
+        "start": "2014-10-09T08:00:00Z", 
+        "master": null, 
+        "location": "A room", 
+        "uid": "6b4fd2f0-8983-4ca8-ab19-ff7fd1301f37", 
+        "data": "{\"type\": \"workshop\", \"people\": [\"Mr Blue\"]}", 
+        "starttz": "Europe/London"
+    }
+},
+{
+    "pk": 1, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 13, 
+        "eventsource": 1, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 2, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 14, 
+        "eventsource": 2, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 3, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 15, 
+        "eventsource": 3, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 4, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 16, 
+        "eventsource": 4, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 5, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 16, 
+        "eventsource": 5, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 6, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 17, 
+        "eventsource": 6, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 7, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 18, 
+        "eventsource": 7, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 8, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 19, 
+        "eventsource": 8, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 9, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 20, 
+        "eventsource": 9, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 10, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 3, 
+        "eventsource": 4, 
+        "annotation": null
+    }
+},
+{
+    "pk": 11, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 3, 
+        "eventsource": 8, 
+        "annotation": null
+    }
+},
+{
+    "pk": 12, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 3, 
+        "eventsource": 9, 
+        "annotation": null
+    }
+},
+{
+    "pk": 13, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 21, 
+        "eventsource": 10, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 14, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 22, 
+        "eventsource": 10, 
+        "annotation": "home"
+    }
+},
+{
+    "pk": 15, 
+    "model": "timetables.eventsourcetag", 
+    "fields": {
+        "thing": 3, 
+        "eventsource": 10, 
+        "annotation": null
+    }
+},
+{
+    "pk": 1, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 6, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 2, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 5, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 3, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 12, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 4, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 11, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 5, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 10, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 6, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 23, 
+        "targetthing": 23, 
+        "annotation": "disabled"
+    }
+}
+]
diff --git a/fixtures/representative/gh-data.csv b/fixtures/representative/gh-data.csv
new file mode 100644
index 0000000..1031f48
--- /dev/null
+++ b/fixtures/representative/gh-data.csv
@@ -0,0 +1,18 @@
+"Tripos Id","Tripos Name","Part Id","Part Name","Subpart Id","Subpart Name","Module Id","Module Name","Series ID","Series Name","Event ID","Title","Type","Start","End","Location","People"
+"4","Simple Tripos","5","Part I","","","13","Module A","1","Series A","6","Blah A","journal club","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","Room A","Dr A"
+"4","Simple Tripos","5","Part I","","","13","Module A","1","Series A","7","Blah A","field trip","2014-10-16T09:00:00+01:00","2014-10-16T10:00:00+01:00","Room B","Dr A#Mr B and Ms C"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","18","D2 Thing","presentation","2014-12-04T09:00:00+00:00","2014-12-04T10:00:00+00:00","Room D","Mr Pink"
+"4","Simple Tripos","6","Part II","","","14","Module B","2","Series B","8","Thing B","practical","2014-11-03T12:00:00+00:00","2014-11-03T13:00:00+00:00","Room B","Mr ABC"
+"4","Simple Tripos","6","Part II","","","15","Module C","3","Series C","9","Thing C","workshop","2015-02-10T14:25:00+00:00","2015-02-10T15:46:00+00:00","Room C","abc12#def34"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","4","Series D 1","13","D1","lecture","2014-10-10T12:00:00+01:00","2014-10-10T13:00:00+01:00","Room D","Prof D"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","4","Series D 1","14","D2","lecture","2015-01-16T12:00:00+00:00","2015-01-16T13:00:00+00:00","Room D","Prof D"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","19","D2 Thing","presentation","2014-12-11T09:00:00+00:00","2014-12-11T10:00:00+00:00","Room D","Mr Pink"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","4","Series D 1","15","D3","lecture","2015-04-24T12:00:00+01:00","2015-04-24T13:00:00+01:00","Room D","Prof D"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","16","D2 Thing","presentation","2014-09-25T09:00:00+01:00","2014-09-25T10:00:00+01:00","Room D","Mr Pink"
+"7","Nested Subject","9","Part II","12","Subject A","20","Module H","9","Series H","23","Event H","","2014-10-30T17:00:00+00:00","2014-10-30T18:00:00+00:00","Room H","Dr H"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","17","D2 Thing","presentation","2014-10-02T09:00:00+01:00","2014-10-02T10:00:00+01:00","Room D","Mr Pink"
+"7","Nested Subject","8","Part I","11","Subject B","17","Module E","6","Series E","20","Event E","class","2014-10-14T14:00:00+01:00","2014-10-14T15:00:00+01:00","Room E","Ms E"
+"7","Nested Subject","8","Part I","10","Subject A","21","Common","10","Shared Subject A Series","24","Intro to Subject A","workshop","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","A room","Mr Blue"
+"7","Nested Subject","9","Part II","12","Subject A","22","Common","10","Shared Subject A Series","24","Intro to Subject A","workshop","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","A room","Mr Blue"
+"7","Nested Subject","8","Part I","11","Subject B","18","Module F","7","Series F","21","Event F","seminar","2014-11-07T08:00:00+00:00","2014-11-07T09:00:00+00:00","Room F","Mr F"
+"7","Nested Subject","9","Part II","12","Subject A","19","Module G","8","Series G","22","Event G","seminar","2015-02-09T13:00:00+00:00","2015-02-09T14:00:00+00:00","Room G","Gee Gson"
diff --git a/fixtures/representative/gh-tree.json b/fixtures/representative/gh-tree.json
new file mode 100644
index 0000000..cd57a29
--- /dev/null
+++ b/fixtures/representative/gh-tree.json
@@ -0,0 +1,423 @@
+{
+    "name": "Timetable",
+    "type": "root",
+    "nodes": {
+        "4": {
+            "id": "4",
+            "name": "Simple Tripos",
+            "type": "course",
+            "nodes": {
+                "5-1": {
+                    "id": "5-1",
+                    "name": "Part I",
+                    "type": "part",
+                    "nodes": {
+                        "13": {
+                            "id": "13",
+                            "name": "Module A",
+                            "type": "module",
+                            "nodes": {
+                                "1": {
+                                    "id": "1",
+                                    "name": "Series A",
+                                    "type": "series",
+                                    "nodes": {
+                                        "6": {
+                                            "id": "6",
+                                            "name": "Blah A",
+                                            "type": "event",
+                                            "event-type": "journal club",
+                                            "start": "2014-10-09T09:00:00+01:00",
+                                            "end": "2014-10-09T10:00:00+01:00",
+                                            "location": "Room A",
+                                            "people": [
+                                                "Dr A"
+                                            ]
+                                        },
+                                        "7": {
+                                            "id": "7",
+                                            "name": "Blah A",
+                                            "type": "event",
+                                            "event-type": "field trip",
+                                            "start": "2014-10-16T09:00:00+01:00",
+                                            "end": "2014-10-16T10:00:00+01:00",
+                                            "location": "Room B",
+                                            "people": [
+                                                "Dr A",
+                                                "Mr B",
+                                                "Ms C"
+                                            ]
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+                "6-3": {
+                    "id": "6-3",
+                    "name": "Part II",
+                    "type": "part",
+                    "nodes": {
+                        "14": {
+                            "id": "14",
+                            "name": "Module B",
+                            "type": "module",
+                            "nodes": {
+                                "2": {
+                                    "id": "2",
+                                    "name": "Series B",
+                                    "type": "series",
+                                    "nodes": {
+                                        "8": {
+                                            "id": "8",
+                                            "name": "Thing B",
+                                            "type": "event",
+                                            "event-type": "practical",
+                                            "start": "2014-11-03T12:00:00+00:00",
+                                            "end": "2014-11-03T13:00:00+00:00",
+                                            "location": "Room B",
+                                            "people": [
+                                                "Mr ABC"
+                                            ]
+                                        }
+                                    }
+                                }
+                            }
+                        },
+                        "15": {
+                            "id": "15",
+                            "name": "Module C",
+                            "type": "module",
+                            "nodes": {
+                                "3": {
+                                    "id": "3",
+                                    "name": "Series C",
+                                    "type": "series",
+                                    "nodes": {
+                                        "9": {
+                                            "id": "9",
+                                            "name": "Thing C",
+                                            "type": "event",
+                                            "event-type": "workshop",
+                                            "start": "2015-02-10T14:25:00+00:00",
+                                            "end": "2015-02-10T15:46:00+00:00",
+                                            "location": "Room C",
+                                            "people": [
+                                                "abc12",
+                                                "def34"
+                                            ]
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
+        "7": {
+            "id": "7",
+            "name": "Nested Subject",
+            "type": "course",
+            "nodes": {
+                "Subject A": {
+                    "id": "Subject A",
+                    "type": "subject",
+                    "name": "Subject A",
+                    "nodes": {
+                        "8-2": {
+                            "id": "8-2",
+                            "name": "Part I",
+                            "type": "part",
+                            "nodes": {
+                                "16": {
+                                    "id": "16",
+                                    "name": "Module D",
+                                    "type": "module",
+                                    "nodes": {
+                                        "4": {
+                                            "id": "4",
+                                            "name": "Series D 1",
+                                            "type": "series",
+                                            "nodes": {
+                                                "13": {
+                                                    "id": "13",
+                                                    "name": "D1",
+                                                    "type": "event",
+                                                    "event-type": "lecture",
+                                                    "start": "2014-10-10T12:00:00+01:00",
+                                                    "end": "2014-10-10T13:00:00+01:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Prof D"
+                                                    ]
+                                                },
+                                                "14": {
+                                                    "id": "14",
+                                                    "name": "D2",
+                                                    "type": "event",
+                                                    "event-type": "lecture",
+                                                    "start": "2015-01-16T12:00:00+00:00",
+                                                    "end": "2015-01-16T13:00:00+00:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Prof D"
+                                                    ]
+                                                },
+                                                "15": {
+                                                    "id": "15",
+                                                    "name": "D3",
+                                                    "type": "event",
+                                                    "event-type": "lecture",
+                                                    "start": "2015-04-24T12:00:00+01:00",
+                                                    "end": "2015-04-24T13:00:00+01:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Prof D"
+                                                    ]
+                                                }
+                                            }
+                                        },
+                                        "5": {
+                                            "id": "5",
+                                            "name": "Series D2",
+                                            "type": "series",
+                                            "nodes": {
+                                                "16": {
+                                                    "id": "16",
+                                                    "name": "D2 Thing",
+                                                    "type": "event",
+                                                    "event-type": "presentation",
+                                                    "start": "2014-09-25T09:00:00+01:00",
+                                                    "end": "2014-09-25T10:00:00+01:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Mr Pink"
+                                                    ]
+                                                },
+                                                "17": {
+                                                    "id": "17",
+                                                    "name": "D2 Thing",
+                                                    "type": "event",
+                                                    "event-type": "presentation",
+                                                    "start": "2014-10-02T09:00:00+01:00",
+                                                    "end": "2014-10-02T10:00:00+01:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Mr Pink"
+                                                    ]
+                                                },
+                                                "18": {
+                                                    "id": "18",
+                                                    "name": "D2 Thing",
+                                                    "type": "event",
+                                                    "event-type": "presentation",
+                                                    "start": "2014-12-04T09:00:00+00:00",
+                                                    "end": "2014-12-04T10:00:00+00:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Mr Pink"
+                                                    ]
+                                                },
+                                                "19": {
+                                                    "id": "19",
+                                                    "name": "D2 Thing",
+                                                    "type": "event",
+                                                    "event-type": "presentation",
+                                                    "start": "2014-12-11T09:00:00+00:00",
+                                                    "end": "2014-12-11T10:00:00+00:00",
+                                                    "location": "Room D",
+                                                    "people": [
+                                                        "Mr Pink"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                },
+                                "21": {
+                                    "id": "21",
+                                    "name": "Common",
+                                    "type": "module",
+                                    "nodes": {
+                                        "10": {
+                                            "id": "10",
+                                            "name": "Shared Subject A Series",
+                                            "type": "series",
+                                            "nodes": {
+                                                "24": {
+                                                    "id": "24",
+                                                    "name": "Intro to Subject A",
+                                                    "type": "event",
+                                                    "event-type": "workshop",
+                                                    "start": "2014-10-09T09:00:00+01:00",
+                                                    "end": "2014-10-09T10:00:00+01:00",
+                                                    "location": "A room",
+                                                    "people": [
+                                                        "Mr Blue"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        },
+                        "9-4": {
+                            "id": "9-4",
+                            "name": "Part II",
+                            "type": "part",
+                            "nodes": {
+                                "19": {
+                                    "id": "19",
+                                    "name": "Module G",
+                                    "type": "module",
+                                    "nodes": {
+                                        "8": {
+                                            "id": "8",
+                                            "name": "Series G",
+                                            "type": "series",
+                                            "nodes": {
+                                                "22": {
+                                                    "id": "22",
+                                                    "name": "Event G",
+                                                    "type": "event",
+                                                    "event-type": "seminar",
+                                                    "start": "2015-02-09T13:00:00+00:00",
+                                                    "end": "2015-02-09T14:00:00+00:00",
+                                                    "location": "Room G",
+                                                    "people": [
+                                                        "Gee Gson"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                },
+                                "20": {
+                                    "id": "20",
+                                    "name": "Module H",
+                                    "type": "module",
+                                    "nodes": {
+                                        "9": {
+                                            "id": "9",
+                                            "name": "Series H",
+                                            "type": "series",
+                                            "nodes": {
+                                                "23": {
+                                                    "id": "23",
+                                                    "name": "Event H",
+                                                    "type": "event",
+                                                    "event-type": "",
+                                                    "start": "2014-10-30T17:00:00+00:00",
+                                                    "end": "2014-10-30T18:00:00+00:00",
+                                                    "location": "Room H",
+                                                    "people": [
+                                                        "Dr H"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                },
+                                "22": {
+                                    "id": "22",
+                                    "name": "Common",
+                                    "type": "module",
+                                    "nodes": {
+                                        "10": {
+                                            "id": "10",
+                                            "name": "Shared Subject A Series",
+                                            "type": "series",
+                                            "nodes": {
+                                                "24": {
+                                                    "id": "24",
+                                                    "name": "Intro to Subject A",
+                                                    "type": "event",
+                                                    "event-type": "workshop",
+                                                    "start": "2014-10-09T09:00:00+01:00",
+                                                    "end": "2014-10-09T10:00:00+01:00",
+                                                    "location": "A room",
+                                                    "people": [
+                                                        "Mr Blue"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+                "Subject B": {
+                    "id": "Subject B",
+                    "type": "subject",
+                    "name": "Subject B",
+                    "nodes": {
+                        "8-5": {
+                            "id": "8-5",
+                            "name": "Part I",
+                            "type": "part",
+                            "nodes": {
+                                "17": {
+                                    "id": "17",
+                                    "name": "Module E",
+                                    "type": "module",
+                                    "nodes": {
+                                        "6": {
+                                            "id": "6",
+                                            "name": "Series E",
+                                            "type": "series",
+                                            "nodes": {
+                                                "20": {
+                                                    "id": "20",
+                                                    "name": "Event E",
+                                                    "type": "event",
+                                                    "event-type": "class",
+                                                    "start": "2014-10-14T14:00:00+01:00",
+                                                    "end": "2014-10-14T15:00:00+01:00",
+                                                    "location": "Room E",
+                                                    "people": [
+                                                        "Ms E"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                },
+                                "18": {
+                                    "id": "18",
+                                    "name": "Module F",
+                                    "type": "module",
+                                    "nodes": {
+                                        "7": {
+                                            "id": "7",
+                                            "name": "Series F",
+                                            "type": "series",
+                                            "nodes": {
+                                                "21": {
+                                                    "id": "21",
+                                                    "name": "Event F",
+                                                    "type": "event",
+                                                    "event-type": "seminar",
+                                                    "start": "2014-11-07T08:00:00+00:00",
+                                                    "end": "2014-11-07T09:00:00+00:00",
+                                                    "location": "Room F",
+                                                    "people": [
+                                                        "Mr F"
+                                                    ]
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/fixtures/representative/structure-verification/django-fixture.json b/fixtures/representative/structure-verification/django-fixture.json
new file mode 100644
index 0000000..f3206b3
--- /dev/null
+++ b/fixtures/representative/structure-verification/django-fixture.json
@@ -0,0 +1,1194 @@
+[
+{
+    "pk": 1, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "tripos", 
+        "parent": null, 
+        "data": "", 
+        "pathid": "p4pmLBPvFQjdJGPWzPW-yahYfT0=", 
+        "fullpath": "tripos", 
+        "type": "", 
+        "fullname": "All Triposes"
+    }
+},
+{
+    "pk": 2, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "user", 
+        "parent": null, 
+        "data": "", 
+        "pathid": "Et6pb-wgWTVmq3VpLJlJWWgzrck=", 
+        "fullpath": "user", 
+        "type": "", 
+        "fullname": "All Users"
+    }
+},
+{
+    "pk": 3, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "hal", 
+        "parent": 2, 
+        "data": "{\"salt\": \"YYmFEIPopckMevmjcJVGkEVf274=\"}", 
+        "pathid": "6cNw3dH9KHajMrM--6Cu-BikfQg=", 
+        "fullpath": "user/hal", 
+        "type": "user", 
+        "fullname": "A Users Calendar"
+    }
+},
+{
+    "pk": 4, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "simple-tripos", 
+        "parent": 1, 
+        "data": "", 
+        "pathid": "MlUWOuWXW7qRoJnpBQjSAx5pE9g=", 
+        "fullpath": "tripos/simple-tripos", 
+        "type": "tripos", 
+        "fullname": "Simple Tripos"
+    }
+},
+{
+    "pk": 5, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "I", 
+        "parent": 4, 
+        "data": "", 
+        "pathid": "sv4CGCwxit9dVfnCk1n15Zuxrm8=", 
+        "fullpath": "tripos/simple-tripos/I", 
+        "type": "part", 
+        "fullname": "Part I"
+    }
+},
+{
+    "pk": 6, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "II", 
+        "parent": 4, 
+        "data": "", 
+        "pathid": "TlMuU-CJWtjv_1ZWoDYvx134yJI=", 
+        "fullpath": "tripos/simple-tripos/II", 
+        "type": "part", 
+        "fullname": "Part II"
+    }
+},
+{
+    "pk": 7, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "nested-subject", 
+        "parent": 1, 
+        "data": "", 
+        "pathid": "bUM7__pG2izMa6ey6dBcYfcYxdg=", 
+        "fullpath": "tripos/nested-subject", 
+        "type": "tripos", 
+        "fullname": "Nested Subject"
+    }
+},
+{
+    "pk": 8, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "I", 
+        "parent": 7, 
+        "data": "", 
+        "pathid": "zpUrgf6k6I_VYLIsDXWSBoHFnzE=", 
+        "fullpath": "tripos/nested-subject/I", 
+        "type": "part", 
+        "fullname": "Part I"
+    }
+},
+{
+    "pk": 9, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "II", 
+        "parent": 7, 
+        "data": "", 
+        "pathid": "IxvwEE76HyEfCGFA0ymMCWgZbh4=", 
+        "fullpath": "tripos/nested-subject/II", 
+        "type": "part", 
+        "fullname": "Part II"
+    }
+},
+{
+    "pk": 10, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "subj-a", 
+        "parent": 8, 
+        "data": "", 
+        "pathid": "JvLOzsX_dgeWcR51JBSHdVkvMBA=", 
+        "fullpath": "tripos/nested-subject/I/subj-a", 
+        "type": "subject", 
+        "fullname": "Subject A"
+    }
+},
+{
+    "pk": 11, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "subj-b", 
+        "parent": 8, 
+        "data": "", 
+        "pathid": "O6H16VH52s5uNh3OraL9egTCWr4=", 
+        "fullpath": "tripos/nested-subject/I/subj-b", 
+        "type": "subject", 
+        "fullname": "Subject B"
+    }
+},
+{
+    "pk": 12, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "subj-a", 
+        "parent": 9, 
+        "data": "", 
+        "pathid": "tyUGbz2hOdCV5EkZvPgvuU8tFjE=", 
+        "fullpath": "tripos/nested-subject/II/subj-a", 
+        "type": "subject", 
+        "fullname": "Subject A"
+    }
+},
+{
+    "pk": 13, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_a", 
+        "parent": 5, 
+        "data": "", 
+        "pathid": "ssnoorNX1YmiSWNEAn0N9vEMNzc=", 
+        "fullpath": "tripos/simple-tripos/I/module_a", 
+        "type": "module", 
+        "fullname": "Module A"
+    }
+},
+{
+    "pk": 14, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_b", 
+        "parent": 6, 
+        "data": "", 
+        "pathid": "LE0DWn9RbW8L2fy54MWOnPw4sDw=", 
+        "fullpath": "tripos/simple-tripos/II/module_b", 
+        "type": "module", 
+        "fullname": "Module B"
+    }
+},
+{
+    "pk": 15, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_c", 
+        "parent": 6, 
+        "data": "", 
+        "pathid": "mw9hI_aHX8jxVe17DqmF8hDJMLs=", 
+        "fullpath": "tripos/simple-tripos/II/module_c", 
+        "type": "module", 
+        "fullname": "Module C"
+    }
+},
+{
+    "pk": 16, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_d", 
+        "parent": 10, 
+        "data": "", 
+        "pathid": "ZiJjJQ5gMD-6qSvcI3yXwrY-lYc=", 
+        "fullpath": "tripos/nested-subject/I/subj-a/module_d", 
+        "type": "module", 
+        "fullname": "Module D"
+    }
+},
+{
+    "pk": 17, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_e", 
+        "parent": 11, 
+        "data": "", 
+        "pathid": "E43to0nxSw6uL4TKan5rfvAftlA=", 
+        "fullpath": "tripos/nested-subject/I/subj-b/module_e", 
+        "type": "module", 
+        "fullname": "Module E"
+    }
+},
+{
+    "pk": 18, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_f", 
+        "parent": 11, 
+        "data": "", 
+        "pathid": "I-z48bz1pxWVv_2SwS_RobnOcew=", 
+        "fullpath": "tripos/nested-subject/I/subj-b/module_f", 
+        "type": "module", 
+        "fullname": "Module F"
+    }
+},
+{
+    "pk": 19, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_g", 
+        "parent": 12, 
+        "data": "", 
+        "pathid": "JhM27mjwSqCwkU335K5hyNXS_2Y=", 
+        "fullpath": "tripos/nested-subject/II/subj-a/module_g", 
+        "type": "module", 
+        "fullname": "Module G"
+    }
+},
+{
+    "pk": 20, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "module_h", 
+        "parent": 12, 
+        "data": "", 
+        "pathid": "untJEcEfOUYMAXVs7OWpyTvlSFU=", 
+        "fullpath": "tripos/nested-subject/II/subj-a/module_h", 
+        "type": "module", 
+        "fullname": "Module H"
+    }
+},
+{
+    "pk": 21, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "common", 
+        "parent": 10, 
+        "data": "", 
+        "pathid": "wlYI2aRxNbYDwSyANMuAiOyADyQ=", 
+        "fullpath": "tripos/nested-subject/I/subj-a/common", 
+        "type": "module", 
+        "fullname": "Common"
+    }
+},
+{
+    "pk": 22, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "common", 
+        "parent": 12, 
+        "data": "", 
+        "pathid": "xnS8_sJZB1cxp0yrcaKIK_ihGdw=", 
+        "fullpath": "tripos/nested-subject/II/subj-a/common", 
+        "type": "module", 
+        "fullname": "Common"
+    }
+},
+{
+    "pk": 23, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "External", 
+        "parent": 4, 
+        "data": "{\r\n    \"external_website_url\": \"https://www.example.org/\"\r\n}", 
+        "pathid": "h01nE8b2A-5I0kcrMjrMagMDZOo=", 
+        "fullpath": "tripos/simple-tripos/External", 
+        "type": "part", 
+        "fullname": "External Part"
+    }
+},
+{
+    "pk": 24, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "disabled_module", 
+        "parent": 23, 
+        "data": "", 
+        "pathid": "GHyFEV_W17d7IrZaejM7BkB_3y8=", 
+        "fullpath": "tripos/simple-tripos/External/disabled_module", 
+        "type": "module", 
+        "fullname": "Disabled Module"
+    }
+},
+{
+    "pk": 25, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "external2", 
+        "parent": 4, 
+        "data": "{\r\n    \"external_website_url\": \"https://www.example.org/2\"\r\n}", 
+        "pathid": "-mKIjmOYdYVwsC-Q_2ZumKEmpuk=", 
+        "fullpath": "tripos/simple-tripos/external2", 
+        "type": "part", 
+        "fullname": "External (no events with URL)"
+    }
+},
+{
+    "pk": 26, 
+    "model": "timetables.thing", 
+    "fields": {
+        "name": "external3", 
+        "parent": 4, 
+        "data": "", 
+        "pathid": "wnWItYPDv6V5tEIWuD_3pczoarY=", 
+        "fullpath": "tripos/simple-tripos/external3", 
+        "type": "part", 
+        "fullname": "External (no events no URL)"
+    }
+},
+{
+    "pk": 1, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series A", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 1, 
+        "data": "{\"location\": \"Room B\", \"people\": [\"Dr A\", \"Mr B and Ms C\"], \"datePattern\": \"Mi1-2 Th 9\"}", 
+        "versionstamp": "2015-05-22T20:05:37.722Z"
+    }
+},
+{
+    "pk": 2, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series B", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 2, 
+        "data": "{\"datePattern\": \"Mi4 M 12\", \"location\": \"Room B\", \"people\": [\"Mr ABC\"]}", 
+        "versionstamp": "2015-05-22T20:16:57.322Z"
+    }
+},
+{
+    "pk": 3, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series C", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 3, 
+        "data": "{\"datePattern\": \"Le4 Tu 2:25-3:46\", \"location\": \"Room C\", \"people\": [\"abc12\", \"def34\"]}", 
+        "versionstamp": "2015-05-22T20:21:01.215Z"
+    }
+},
+{
+    "pk": 4, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series D 1", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 4, 
+        "data": "{\"location\": \"Room D\", \"people\": [\"Prof D\"], \"datePattern\": \"Mi1 Le1 Ea1 F 12\"}", 
+        "versionstamp": "2015-05-22T20:30:20.208Z"
+    }
+},
+{
+    "pk": 5, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series D2", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 5, 
+        "data": "{\"datePattern\": \"Mi-1,0,9-10 Th 9\", \"location\": \"Room D\", \"people\": [\"Mr Pink\"]}", 
+        "versionstamp": "2015-05-22T20:38:01.420Z"
+    }
+},
+{
+    "pk": 6, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series E", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 6, 
+        "data": "{\"datePattern\": \"Mi1 Tu 2\", \"location\": \"Room E\", \"people\": [\"Ms E\"]}", 
+        "versionstamp": "2015-05-22T20:42:35.392Z"
+    }
+},
+{
+    "pk": 7, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series F", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 7, 
+        "data": "{\"datePattern\": \"Mi5 F 8\", \"location\": \"Room F\", \"people\": [\"Mr F\"]}", 
+        "versionstamp": "2015-05-22T20:44:11.531Z"
+    }
+},
+{
+    "pk": 8, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series G", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 8, 
+        "data": "{\"datePattern\": \"Le4 M 1\", \"location\": \"Room G\", \"people\": [\"Gee Gson\"]}", 
+        "versionstamp": "2015-05-22T20:49:19.770Z"
+    }
+},
+{
+    "pk": 9, 
+    "model": "timetables.eventsource", 
+    "fields": {
+        "sourceurl": null, 
+        "sourcetype": "pattern", 
+        "title": "Series H", 
+        "sourcefile": "", 
+        "current": true, 
+        "master": 9, 
+        "data": "{\"datePattern\": \"Mi4 Th 5\", \"location\": \"Room H\", \"people\": [\"Dr H\"]}", 
+        "versionstamp": "2015-05-22T20:52:05.040Z"
+    }
+},
+{
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+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 11, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 5, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 10, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 6, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 23, 
+        "targetthing": 23, 
+        "annotation": "disabled"
+    }
+},
+{
+    "pk": 7, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 3, 
+        "targetthing": 23, 
+        "annotation": "admin"
+    }
+},
+{
+    "pk": 8, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 25, 
+        "targetthing": 25, 
+        "annotation": "disabled"
+    }
+},
+{
+    "pk": 9, 
+    "model": "timetables.thingtag", 
+    "fields": {
+        "thing": 26, 
+        "targetthing": 26, 
+        "annotation": "disabled"
+    }
+}
+]
diff --git a/fixtures/representative/structure-verification/events.csv b/fixtures/representative/structure-verification/events.csv
new file mode 100644
index 0000000..18ec4e8
--- /dev/null
+++ b/fixtures/representative/structure-verification/events.csv
@@ -0,0 +1,19 @@
+"Tripos Id","Tripos Name","Part Id","Part Name","Subpart Id","Subpart Name","Module Id","Module Name","Series ID","Series Name","Event ID","Title","Type","Start","End","Location","People"
+"4","Simple Tripos","5","Part I","","","13","Module A","1","Series A","6","Blah A","journal club","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","Room A","Dr A"
+"4","Simple Tripos","5","Part I","","","13","Module A","1","Series A","7","Blah A","field trip","2014-10-16T09:00:00+01:00","2014-10-16T10:00:00+01:00","Room B","Dr A#Mr B and Ms C"
+"4","Simple Tripos","6","Part II","","","14","Module B","2","Series B","8","Thing B","practical","2014-11-03T12:00:00+00:00","2014-11-03T13:00:00+00:00","Room B","Mr ABC"
+"4","Simple Tripos","6","Part II","","","15","Module C","3","Series C","9","Thing C","workshop","2015-02-10T14:25:00+00:00","2015-02-10T15:46:00+00:00","Room C","abc12#def34"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","4","Series D 1","13","D1","lecture","2014-10-10T12:00:00+01:00","2014-10-10T13:00:00+01:00","Room D","Prof D"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","4","Series D 1","14","D2","lecture","2015-01-16T12:00:00+00:00","2015-01-16T13:00:00+00:00","Room D","Prof D"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","4","Series D 1","15","D3","lecture","2015-04-24T12:00:00+01:00","2015-04-24T13:00:00+01:00","Room D","Prof D"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","16","D2 Thing","presentation","2014-09-25T09:00:00+01:00","2014-09-25T10:00:00+01:00","Room D","Mr Pink"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","17","D2 Thing","presentation","2014-10-02T09:00:00+01:00","2014-10-02T10:00:00+01:00","Room D","Mr Pink"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","18","D2 Thing","presentation","2014-12-04T09:00:00+00:00","2014-12-04T10:00:00+00:00","Room D","Mr Pink"
+"7","Nested Subject","8","Part I","10","Subject A","16","Module D","5","Series D2","19","D2 Thing","presentation","2014-12-11T09:00:00+00:00","2014-12-11T10:00:00+00:00","Room D","Mr Pink"
+"7","Nested Subject","8","Part I","11","Subject B","17","Module E","6","Series E","20","Event E","class","2014-10-14T14:00:00+01:00","2014-10-14T15:00:00+01:00","Room E","Ms E"
+"7","Nested Subject","8","Part I","11","Subject B","18","Module F","7","Series F","21","Event F","seminar","2014-11-07T08:00:00+00:00","2014-11-07T09:00:00+00:00","Room F","Mr F"
+"7","Nested Subject","9","Part II","12","Subject A","19","Module G","8","Series G","22","Event G","seminar","2015-02-09T13:00:00+00:00","2015-02-09T14:00:00+00:00","Room G","Gee Gson"
+"7","Nested Subject","9","Part II","12","Subject A","20","Module H","9","Series H","23","Event H","","2014-10-30T17:00:00+00:00","2014-10-30T18:00:00+00:00","Room H","Dr H"
+"7","Nested Subject","8","Part I","10","Subject A","21","Common","10","Shared Subject A Series","24","Intro to Subject A","workshop","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","A room","Mr Blue"
+"7","Nested Subject","9","Part II","12","Subject A","22","Common","10","Shared Subject A Series","24","Intro to Subject A","workshop","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","A room","Mr Blue"
+"4","Simple Tripos","23","External Part","","","24","Disabled Module","11","Disabled Series","25","Disabled Event","journal club","2014-10-09T09:00:00+01:00","2014-10-09T10:00:00+01:00","blah","hi"
diff --git a/fixtures/representative/structure-verification/structure.json b/fixtures/representative/structure-verification/structure.json
new file mode 100644
index 0000000..aea3b49
--- /dev/null
+++ b/fixtures/representative/structure-verification/structure.json
@@ -0,0 +1,102 @@
+{
+    "nodes": {
+        "4": {
+            "nodes": {
+                "25": {
+                    "type": "part", 
+                    "nodes": {}, 
+                    "data": {
+                        "external": "https://www.example.org/2"
+                    }, 
+                    "id": 25, 
+                    "name": "External (no events with URL)"
+                }, 
+                "26": {
+                    "type": "part", 
+                    "nodes": {}, 
+                    "data": null, 
+                    "id": 26, 
+                    "name": "External (no events no URL)"
+                }, 
+                "5": {
+                    "type": "part", 
+                    "nodes": {}, 
+                    "data": null, 
+                    "id": 5, 
+                    "name": "Part I"
+                }, 
+                "6": {
+                    "type": "part", 
+                    "nodes": {}, 
+                    "data": null, 
+                    "id": 6, 
+                    "name": "Part II"
+                }, 
+                "23": {
+                    "type": "part", 
+                    "nodes": {}, 
+                    "data": {
+                        "external": "https://www.example.org/"
+                    }, 
+                    "id": 23, 
+                    "name": "External Part"
+                }
+            }, 
+            "type": "course", 
+            "id": 4, 
+            "name": "Simple Tripos"
+        }, 
+        "7": {
+            "nodes": {
+                "10": {
+                    "nodes": {
+                        "8": {
+                            "type": "part", 
+                            "nodes": {}, 
+                            "data": null, 
+                            "id": 8, 
+                            "name": "Part I"
+                        }
+                    }, 
+                    "type": "subject", 
+                    "id": 10, 
+                    "name": "Subject A"
+                }, 
+                "11": {
+                    "nodes": {
+                        "8": {
+                            "type": "part", 
+                            "nodes": {}, 
+                            "data": null, 
+                            "id": 8, 
+                            "name": "Part I"
+                        }
+                    }, 
+                    "type": "subject", 
+                    "id": 11, 
+                    "name": "Subject B"
+                }, 
+                "12": {
+                    "nodes": {
+                        "9": {
+                            "type": "part", 
+                            "nodes": {}, 
+                            "data": null, 
+                            "id": 9, 
+                            "name": "Part II"
+                        }
+                    }, 
+                    "type": "subject", 
+                    "id": 12, 
+                    "name": "Subject A"
+                }
+            }, 
+            "type": "course", 
+            "id": 7, 
+            "name": "Nested Subject"
+        }
+    }, 
+    "type": "root", 
+    "id": 0, 
+    "name": "Timetable"
+}