diff --git a/datagateway_api/common/database/models.py b/datagateway_api/common/database/models.py
index 1852def6..d0796c95 100644
--- a/datagateway_api/common/database/models.py
+++ b/datagateway_api/common/database/models.py
@@ -148,7 +148,15 @@ def _nest_string_include(self, dictionary, include):
 
     def get_related_entity(self, entity):
         """
-        Given a string for the related entity name, return the related entity
+        Given a string for the related entity name, return the related entity. This
+        function is used to retrieve a related entity as a result of an include filter.
+
+        Some related entities have a plural name (so end with an 's') so this is
+        checked. If `entity` contains a name which is a singular, `entity` is
+        uppercased (table names are defined in upper case, as seen in `__tablename__` in
+        the entity classes lower down in this file). Both related entity name types
+        (singular and plural) are used to retrieve the actual related entity.
+
         :param entity: String - The name of the entity
         :return: The entity
         """
diff --git a/datagateway_api/src/resources/entities/entity_map.py b/datagateway_api/src/resources/entities/entity_map.py
index a3b3c023..6bb74659 100644
--- a/datagateway_api/src/resources/entities/entity_map.py
+++ b/datagateway_api/src/resources/entities/entity_map.py
@@ -76,6 +76,7 @@ def create_entity_models():
                 or relationship_class.direction.name == "ONETOMANY"
             ):
                 entity_underscore_strip = relationship_name.strip("_")
+                # Checking for plurals on a related ICAT entity
                 if entity_underscore_strip[-1] == "s":
                     pascal_case = (
                         entity_underscore_strip[0].upper() + entity_underscore_strip[1:]