Pass the fixed ChecboxesField type of component inside the controller itself rather than in yaml files

src/server/common/forms/definitions/example-grant-with-auth.yaml

@@ -394,10 +394,6 @@ pages:
     id: 88d7b067-68c2-4fe1-9a9a-ea98f0752e03
   - title: Select all the eligible land parcels for the location of your woodland
     controller: CommonSelectLandParcelPageController
-    components:
-      - name: landParcels
-        type: CheckboxesField
-        title: Select land parcels
     config:
       enableMultipleParcelSelect: true
       topSection: |

src/server/common/forms/definitions/example-grant-with-task-list.yaml

@@ -236,10 +236,6 @@ pages:
 
   - title: Select land parcel for actions
     controller: CommonSelectLandParcelPageController
-    components:
-      - name: landParcels
-        type: CheckboxesField
-        title: Select land parcels
     config:
       enableMultipleParcelSelect: false
       bottomSection: |

src/server/land-grants/common/common-select-parcel/common-select-land-parcel-page.controller.js

@@ -3,6 +3,7 @@ import LandGrantsQuestionWithAuthCheckController from '../../controllers/auth/la
 import { fetchParcels } from '../../services/land-grants.service.js'
 import { mapParcelsToViewModel } from '../../view-models/parcel.view-model.js'
 import { getParcelIdFromQuery, getParcelIdsFromPayload } from '../../utils/parcel-request.utils.js'
+import { ComponentType } from '@defra/forms-model'
 
 export default class CommonSelectLandParcelPageController extends LandGrantsQuestionWithAuthCheckController {
   viewName = 'common-select-land-parcel'
@@ -14,12 +15,37 @@ export default class CommonSelectLandParcelPageController extends LandGrantsQues
    *   config:
    *     enableMultipleParcelSelect: true
    *
+   * Ensures a `landParcels` CheckboxesField component exists on the page.
+   * If not defined in YAML, it is injected here so the form schema and state
+   * are consistent across all journeys.
+   *
    * @param {FormModel} model
-   * @param {import('@defra/forms-model').Page} pageDef
+   * @param {PageQuestion} pageDef
    */
   constructor(model, pageDef) {
-    super(model, pageDef)
     const config = model.def.metadata?.pageConfig?.[pageDef.path] ?? {}
+
+    const existing = pageDef.components?.find((c) => c.name === 'landParcels')
+    /** @type {import('@defra/forms-model').PageQuestion} */
+    const patchedPageDef = {
+      ...pageDef,
+      components: existing
+        ? pageDef.components
+        : [
+            ...(pageDef.components ?? []),
+            {
+              type: ComponentType.CheckboxesField,
+              name: 'landParcels',
+              title: 'Select land parcels',
+              list: 'landParcels',
+              options: {
+                required: true
+              }
+            }
+          ]
+    }
+    super(model, patchedPageDef)
+
     this.enableMultipleParcelSelect = config.enableMultipleParcelSelect === true
     this.topSection = config.topSection || ''
     this.bottomSection = config.bottomSection || ''
@@ -141,6 +167,7 @@ export default class CommonSelectLandParcelPageController extends LandGrantsQues
 
 /**
  * @import { FormContext, AnyFormRequest } from '@defra/forms-engine-plugin/engine/types.js'
+ * @import { PageQuestion } from '@defra/forms-model'
  * @import { FormModel } from '@defra/forms-engine-plugin/engine/models/index.js'
- * @import { ResponseObject, ResponseToolkit } from '@hapi/hapi'
+ * @import { ResponseToolkit } from '@hapi/hapi'
  */

src/server/land-grants/common/common-select-parcel/common-select-land-parcel-page.controller.test.js

@@ -68,6 +68,32 @@ describe('CommonSelectLandParcelPageController', () => {
 
   afterEach(vi.clearAllMocks)
 
+  describe('constructor', () => {
+    it('does NOT inject CheckboxesField if landParcels already exists', () => {
+      const model = {
+        def: { metadata: { pageConfig: {} } }
+      }
+
+      const existingComponent = {
+        type: 'CheckboxesField',
+        name: 'landParcels',
+        title: 'Existing'
+      }
+
+      const pageDef = {
+        path: '/test',
+        components: [existingComponent]
+      }
+
+      const controller = new CommonSelectLandParcelPageController(model, pageDef)
+
+      const components =
+        controller.form?.definition?.pages?.[0]?.components || controller.pageDef?.components || pageDef.components
+
+      expect(components).toEqual([existingComponent])
+    })
+  })
+
   describe('resolveParcelIds', () => {
     it('returns payload values for POST', () => {
       const controller = createController()