diff --git a/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/relation-type.repository.ts b/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/relation-type.repository.ts
index 9e4c5d0171..dcf2fee07a 100644
--- a/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/relation-type.repository.ts
+++ b/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/relation-type.repository.ts
@@ -66,6 +66,12 @@ export class UmbRelationTypeRepository implements UmbTreeRepository, UmbDetailRe
 		return { data, error, asObservable: () => this.#treeStore!.rootItems };
 	}
 
+	//TODO RelationTypes can't have children. But this method is required by the tree interface.
+	async requestTreeItemsOf(parentKey: string | null) {
+		const error: ProblemDetailsModel = { title: 'Not implemented' };
+		return { data: undefined, error };
+	}
+
 	async requestTreeItems(keys: Array<string>) {
 		await this.#init;
 
diff --git a/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/sources/index.ts b/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/sources/index.ts
index 261832c5f4..cd64590110 100644
--- a/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/sources/index.ts
+++ b/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/repository/sources/index.ts
@@ -1,7 +1,7 @@
 import type { DataSourceResponse } from '@umbraco-cms/models';
-import type { EntityTreeItemModel, PagedEntityTreeItemModel } from '@umbraco-cms/backend-api';
+import { EntityTreeItemResponseModel, PagedEntityTreeItemResponseModel } from '@umbraco-cms/backend-api';
 
 export interface RelationTypeTreeDataSource {
-	getRootItems(): Promise<DataSourceResponse<PagedEntityTreeItemModel>>;
-	getItems(key: Array<string>): Promise<DataSourceResponse<EntityTreeItemModel[]>>;
+	getRootItems(): Promise<DataSourceResponse<PagedEntityTreeItemResponseModel>>;
+	getItems(key: Array<string>): Promise<DataSourceResponse<EntityTreeItemResponseModel[]>>;
 }
diff --git a/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/workspace/relation-type-workspace.context.ts b/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/workspace/relation-type-workspace.context.ts
index 0342da9da1..4ce10aa4b5 100644
--- a/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/workspace/relation-type-workspace.context.ts
+++ b/src/Umbraco.Web.UI.Client/src/backoffice/settings/relation-types/workspace/relation-type-workspace.context.ts
@@ -1,13 +1,14 @@
 import { UmbWorkspaceContext } from '../../../shared/components/workspace/workspace-context/workspace-context';
-import { UmbWorkspaceEntityContextInterface } from '../../../shared/components/workspace/workspace-context/workspace-entity-context.interface';
 import { UmbRelationTypeRepository } from '../repository/relation-type.repository';
+import { UmbEntityWorkspaceContextInterface } from '../../../shared/components/workspace/workspace-context/workspace-entity-context.interface';
 import type { RelationTypeBaseModel, RelationTypeResponseModel } from '@umbraco-cms/backend-api';
+
 import { ObjectState } from '@umbraco-cms/observable-api';
 import { UmbControllerHostInterface } from '@umbraco-cms/controller';
 
 export class UmbRelationTypeWorkspaceContext
 	extends UmbWorkspaceContext<UmbRelationTypeRepository>
-	implements UmbWorkspaceEntityContextInterface<RelationTypeResponseModel | undefined>
+	implements UmbEntityWorkspaceContextInterface<RelationTypeResponseModel | undefined>
 {
 	#data = new ObjectState<RelationTypeResponseModel | undefined>(undefined);
 	data = this.#data.asObservable();
diff --git a/src/Umbraco.Web.UI.Client/src/core/mocks/data/relation-type.data.ts b/src/Umbraco.Web.UI.Client/src/core/mocks/data/relation-type.data.ts
index 7d95a4bea2..6526d93f3b 100644
--- a/src/Umbraco.Web.UI.Client/src/core/mocks/data/relation-type.data.ts
+++ b/src/Umbraco.Web.UI.Client/src/core/mocks/data/relation-type.data.ts
@@ -1,6 +1,6 @@
 import { UmbEntityData } from './entity.data';
-import { createEntityTreeItem, createFolderTreeItem } from './utils';
-import type { EntityTreeItemModel, FolderTreeItemModel, RelationTypeResponseModel } from '@umbraco-cms/backend-api';
+import { createEntityTreeItem } from './utils';
+import type { EntityTreeItemResponseModel, RelationTypeResponseModel } from '@umbraco-cms/backend-api';
 
 // TODO: investigate why we don't get an entity type as part of the RelationTypeResponseModel
 export const data: Array<RelationTypeResponseModel> = [
@@ -71,7 +71,7 @@ export const data: Array<RelationTypeResponseModel> = [
 	},
 ];
 
-export const treeData: Array<EntityTreeItemModel> = [
+export const treeData: Array<EntityTreeItemResponseModel> = [
 	{
 		key: 'e0d39ff5-71d8-453f-b682-9d8d31ee5e06',
 		$type: 'EntityTreeItemViewModel',
@@ -130,18 +130,18 @@ class UmbRelationTypeData extends UmbEntityData<RelationTypeResponseModel> {
 	}
 
 	//TODO Can relation types have children?
-	getTreeRoot(): Array<FolderTreeItemModel> {
+	getTreeRoot(): Array<EntityTreeItemResponseModel> {
 		const rootItems = this.treeData;
 		return rootItems.map((item) => createEntityTreeItem(item));
 	}
 
 	//TODO Can relation types have children?
-	getTreeItemChildren(key: string): Array<FolderTreeItemModel> {
+	getTreeItemChildren(key: string): Array<EntityTreeItemResponseModel> {
 		const childItems = this.treeData.filter((item) => item.parentKey === key);
 		return childItems.map((item) => createEntityTreeItem(item));
 	}
 
-	getTreeItem(keys: Array<string>): Array<FolderTreeItemModel> {
+	getTreeItem(keys: Array<string>): Array<EntityTreeItemResponseModel> {
 		const items = this.treeData.filter((item) => keys.includes(item.key ?? ''));
 		return items.map((item) => createEntityTreeItem(item));
 	}