diff --git a/package-lock.json b/package-lock.json
index aabae2381..5d375a04c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,7 +10,7 @@
       "hasInstallScript": true,
       "license": "SEE LICENSE IN LICENSE",
       "dependencies": {
-        "@defra/forms-model": "^3.0.575",
+        "@defra/forms-model": "^3.0.579",
         "@defra/hapi-tracing": "^1.26.0",
         "@elastic/ecs-pino-format": "^1.5.0",
         "@hapi/boom": "^10.0.1",
@@ -2298,9 +2298,9 @@
       }
     },
     "node_modules/@defra/forms-model": {
-      "version": "3.0.575",
-      "resolved": "https://registry.npmjs.org/@defra/forms-model/-/forms-model-3.0.575.tgz",
-      "integrity": "sha512-U6eJ34ukuaZaWs8jkGxi/lVwV36R+KlN1zAoz/IuW0KDehrXbSOmaI7NJEFEu4vSniCWctImjxVkNbsJ8h1xGg==",
+      "version": "3.0.579",
+      "resolved": "https://registry.npmjs.org/@defra/forms-model/-/forms-model-3.0.579.tgz",
+      "integrity": "sha512-X5kqcIlCzYjKkeUatdTZqL5bAPyJMXdKVJWU44GhktH26P28GlQdspAF9OWBz4oNF0cegDiCOLTR3DKyk6zvaw==",
       "license": "OGL-UK-3.0",
       "dependencies": {
         "@joi/date": "^2.1.1",
diff --git a/package.json b/package.json
index aa53da8f4..0b044e31c 100644
--- a/package.json
+++ b/package.json
@@ -70,7 +70,7 @@
   },
   "license": "SEE LICENSE IN LICENSE",
   "dependencies": {
-    "@defra/forms-model": "^3.0.575",
+    "@defra/forms-model": "^3.0.579",
     "@defra/hapi-tracing": "^1.26.0",
     "@elastic/ecs-pino-format": "^1.5.0",
     "@hapi/boom": "^10.0.1",
diff --git a/src/server/plugins/engine/components/DeclarationField.test.ts b/src/server/plugins/engine/components/DeclarationField.test.ts
index bfb8a41a4..be89fd504 100644
--- a/src/server/plugins/engine/components/DeclarationField.test.ts
+++ b/src/server/plugins/engine/components/DeclarationField.test.ts
@@ -186,7 +186,7 @@ describe('DeclarationField', () => {
         const answer2 = getAnswer(field, state2)
 
         expect(answer1).toBe('I understand and agree')
-        expect(answer2).toBe('')
+        expect(answer2).toBe('Not provided')
       })
 
       it('returns payload from state', () => {
@@ -197,7 +197,7 @@ describe('DeclarationField', () => {
         const payload2 = field.getFormDataFromState(state2)
 
         expect(payload1).toEqual(getFormData('true'))
-        expect(payload2).toEqual(getFormData())
+        expect(payload2).toEqual(getFormData('unchecked'))
       })
 
       it('returns value from state', () => {
@@ -208,7 +208,7 @@ describe('DeclarationField', () => {
         const value2 = field.getFormValueFromState(state2)
 
         expect(value1).toBe('true')
-        expect(value2).toBeUndefined()
+        expect(value2).toBe('unchecked')
       })
 
       it('returns context for conditions and form submission', () => {
@@ -246,7 +246,6 @@ describe('DeclarationField', () => {
             label: { text: def.title },
             name: 'myComponent',
             attributes: {},
-            values: [],
             content: 'Lorem ipsum dolar sit amet',
             id: 'myComponent',
             fieldset: {
@@ -257,7 +256,8 @@ describe('DeclarationField', () => {
             items: [
               {
                 value: 'true',
-                text: 'I understand and agree'
+                text: 'I understand and agree',
+                checked: true
               }
             ]
           })
@@ -276,10 +276,16 @@ describe('DeclarationField', () => {
 
         expect(viewModel).toEqual(
           expect.objectContaining({
-            values: ['true'],
             hint: {
               text: 'Please read and confirm the following'
-            }
+            },
+            items: [
+              {
+                value: 'true',
+                text: 'I understand and agree',
+                checked: true
+              }
+            ]
           })
         )
       })
@@ -301,14 +307,39 @@ describe('DeclarationField', () => {
         collection = new ComponentCollection([def], { model })
         field = collection.fields[0]
 
-        const viewModel = field.getViewModel(getFormData(['unchecked', 'true']))
+        const viewModel = field.getViewModel(getFormData(['true']))
+
+        expect(viewModel).toEqual(
+          expect.objectContaining({
+            items: [
+              {
+                value: 'true',
+                text: 'I consent to the processing of my personal data',
+                checked: true
+              }
+            ]
+          })
+        )
+      })
+
+      it('sets checkbox as unchecked', () => {
+        def = {
+          ...def,
+          hint: 'Please read and confirm the following'
+        } satisfies DeclarationFieldComponent
+
+        collection = new ComponentCollection([def], { model })
+        field = collection.fields[0]
+
+        const viewModel = field.getViewModel(getFormData(undefined))
 
         expect(viewModel).toEqual(
           expect.objectContaining({
             items: [
               {
                 value: 'true',
-                text: 'I consent to the processing of my personal data'
+                text: 'I understand and agree',
+                checked: false
               }
             ]
           })
diff --git a/src/server/plugins/engine/components/DeclarationField.ts b/src/server/plugins/engine/components/DeclarationField.ts
index f328abc19..8584d6dc7 100644
--- a/src/server/plugins/engine/components/DeclarationField.ts
+++ b/src/server/plugins/engine/components/DeclarationField.ts
@@ -68,12 +68,12 @@ export class DeclarationField extends FormComponent {
 
   getFormValueFromState(state: FormSubmissionState) {
     const { name } = this
-    return state[name] === true ? 'true' : undefined
+    return state[name] === true ? 'true' : 'unchecked'
   }
 
   getFormDataFromState(state: FormSubmissionState): FormPayload {
     const { name } = this
-    return { [name]: state[name] === true ? 'true' : undefined }
+    return { [name]: state[name] === true ? 'true' : 'unchecked' }
   }
 
   getStateFromValidForm(payload: FormPayload): FormState {
@@ -98,7 +98,7 @@ export class DeclarationField extends FormComponent {
   }
 
   getDisplayStringFromFormValue(value: FormValue | FormPayload): string {
-    return value ? this.declarationConfirmationLabel : ''
+    return value === 'true' ? this.declarationConfirmationLabel : 'Not provided'
   }
 
   getViewModel(payload: FormPayload, errors?: FormSubmissionError[]) {
@@ -110,6 +110,7 @@ export class DeclarationField extends FormComponent {
       content,
       declarationConfirmationLabel = defaultDeclarationConfirmationLabel
     } = this
+    const isChecked = !!payload[this.name]
     return {
       ...super.getViewModel(payload, errors),
       hint: hint ? { text: hint } : undefined,
@@ -119,11 +120,11 @@ export class DeclarationField extends FormComponent {
         }
       },
       content,
-      values: payload[this.name],
       items: [
         {
           text: declarationConfirmationLabel,
-          value: 'true'
+          value: 'true',
+          checked: isChecked
         }
       ]
     }
diff --git a/src/server/plugins/engine/components/helpers/components.test.ts b/src/server/plugins/engine/components/helpers/components.test.ts
index 03e7a07fd..096f14595 100644
--- a/src/server/plugins/engine/components/helpers/components.test.ts
+++ b/src/server/plugins/engine/components/helpers/components.test.ts
@@ -1,5 +1,6 @@
 import {
   ComponentType,
+  type DeclarationFieldComponent,
   type EastingNorthingFieldComponent,
   type LatLongFieldComponent,
   type NationalGridFieldNumberFieldComponent,
@@ -11,6 +12,7 @@ import {
   getAnswerMarkdown
 } from '~/src/server/plugins/engine/components/helpers/components.js'
 import {
+  DeclarationField,
   EastingNorthingField,
   LatLongField,
   NationalGridFieldNumberField,
@@ -216,6 +218,89 @@ describe('Location field formatting', () => {
     })
   })
 
+  describe('DeclarationField', () => {
+    let field: DeclarationField
+
+    beforeEach(() => {
+      const def: DeclarationFieldComponent = {
+        type: ComponentType.DeclarationField,
+        name: 'declField',
+        title: 'Declaration title',
+        content: '# markup heading',
+        options: {}
+      }
+      field = new DeclarationField(def, { model })
+    })
+
+    it('formats correctly when agreed', () => {
+      const state = {
+        declField: true
+      }
+
+      const answer = getAnswer(field, state, { format: 'email' })
+      expect(answer).toBe('I understand and agree\n')
+    })
+
+    it('formats correctly when not agreed', () => {
+      const state = {
+        declField: false
+      }
+
+      const answer = getAnswer(field, state, { format: 'email' })
+      expect(answer).toBe('Not provided\n')
+    })
+
+    it('formats for data output when agreed', () => {
+      const state = {
+        declField: true
+      }
+
+      const answer = getAnswer(field, state, { format: 'data' })
+      expect(answer).toBe('true')
+    })
+
+    it('formats for data output when not agreed', () => {
+      const state = {
+        declField: false
+      }
+
+      const answer = getAnswer(field, state, { format: 'data' })
+      expect(answer).toBe('false')
+    })
+
+    it('formats for data output when no value', () => {
+      const state = {}
+
+      const answer = getAnswer(field, state, { format: 'data' })
+      expect(answer).toBe('false')
+    })
+
+    it('formats for summary display when agreed', () => {
+      const state = {
+        declField: true
+      }
+
+      const answer = getAnswer(field, state, { format: 'summary' })
+      expect(answer).toBe('I understand and agree')
+    })
+
+    it('formats for summary display when not agreed', () => {
+      const state = {
+        declField: false
+      }
+
+      const answer = getAnswer(field, state, { format: 'summary' })
+      expect(answer).toBe('Not provided')
+    })
+
+    it('formats for summary display when no value', () => {
+      const state = {}
+
+      const answer = getAnswer(field, state, { format: 'summary' })
+      expect(answer).toBe('Not provided')
+    })
+  })
+
   describe('getAnswerMarkdown', () => {
     it('formats EastingNorthingField correctly', () => {
       const def: EastingNorthingFieldComponent = {
diff --git a/src/server/plugins/engine/models/SummaryViewModel.test.ts b/src/server/plugins/engine/models/SummaryViewModel.test.ts
index 65ebd13ab..b9c5d254b 100644
--- a/src/server/plugins/engine/models/SummaryViewModel.test.ts
+++ b/src/server/plugins/engine/models/SummaryViewModel.test.ts
@@ -1,3 +1,9 @@
+import {
+  type FormDefinition,
+  type PageQuestion,
+  type RadiosFieldComponent
+} from '@defra/forms-model'
+
 import { FORM_PREFIX } from '~/src/server/constants.js'
 import {
   FormModel,
@@ -66,7 +72,7 @@ describe('SummaryViewModel', () => {
         'Pizzas',
         'Pizza'
       ],
-      values: ['Collection', 'Not supplied'],
+      values: ['Collection', 'Not provided'],
       answers: ['Collection', ''],
       names: ['orderType', 'pizza']
     },
@@ -281,6 +287,49 @@ describe('SummaryViewModel', () => {
       })
     }
   )
+
+  it('should use correct summary labels', () => {
+    request.query.force = '' // Preview URL '?force'
+    const state = {
+      $$__referenceNumber: 'foobar',
+      orderType: 'collection',
+      pizza: []
+    } satisfies FormState
+
+    // Setup an optional question
+    const definitionOptional = structuredClone(definition) as FormDefinition
+    const firstPage = definitionOptional.pages[0] as PageQuestion
+    const firstComponent = firstPage.components[0] as RadiosFieldComponent
+    firstComponent.options.required = false
+
+    const model = new FormModel(definitionOptional, {
+      basePath: `${FORM_PREFIX}/test`
+    })
+
+    context = model.getFormContext(request, state)
+
+    const page = createPage(model, definition.pages[2])
+
+    summaryViewModel = new SummaryViewModel(request, page, context)
+
+    expect(summaryViewModel.details).toHaveLength(2)
+
+    const [details1, details2] = summaryViewModel.details
+
+    expect(details1.items[0]).toMatchObject({
+      name: 'orderType',
+      value: 'Collection',
+      title: 'How you would like to receive your pizza (optional)',
+      label: 'How would you like to receive your pizza?'
+    })
+
+    expect(details2.items[0]).toMatchObject({
+      name: 'pizza',
+      value: '',
+      title: 'Pizzas',
+      label: 'Pizza'
+    })
+  })
 })
 
 describe('SummaryPageController', () => {
@@ -342,7 +391,7 @@ describe('SummaryPageController', () => {
       )
     })
 
-    it('should display default page title for v2 form when title not supplied', () => {
+    it('should display default page title for v2 form when title not provided', () => {
       const state: FormState = {
         $$__referenceNumber: 'foobar',
         orderType: 'collection',
diff --git a/src/server/plugins/engine/models/SummaryViewModel.ts b/src/server/plugins/engine/models/SummaryViewModel.ts
index 41c6c682e..0e90f9271 100644
--- a/src/server/plugins/engine/models/SummaryViewModel.ts
+++ b/src/server/plugins/engine/models/SummaryViewModel.ts
@@ -104,7 +104,7 @@ export class SummaryViewModel {
           },
           value: {
             classes: 'app-prose-scope',
-            html: item.value || 'Not supplied'
+            html: item.value || 'Not provided'
           },
           actions: {
             items
@@ -204,7 +204,7 @@ function ItemRepeat(
  * Creates a form field detail item
  * @see {@link DetailItemField}
  */
-function ItemField(
+export function ItemField(
   page: PageControllerClass,
   state: FormState,
   field: Field,
@@ -216,7 +216,10 @@ function ItemField(
   return {
     name: field.name,
     label: field.title,
-    title: field.label,
+    title:
+      field.options.required === false
+        ? `${field.label} (optional)`
+        : field.label,
     error: field.getFirstError(options.errors),
     value: getAnswer(field, state),
     href: getPageHref(page, options.path, {
diff --git a/src/server/plugins/engine/pageControllers/RepeatPageController.ts b/src/server/plugins/engine/pageControllers/RepeatPageController.ts
index 4368e24a8..3c6296c4b 100644
--- a/src/server/plugins/engine/pageControllers/RepeatPageController.ts
+++ b/src/server/plugins/engine/pageControllers/RepeatPageController.ts
@@ -422,7 +422,7 @@ export class RepeatPageController extends QuestionPageController {
             text: `${title} ${index + 1}`
           },
           value: {
-            text: itemDisplayText || 'Not supplied'
+            text: itemDisplayText || 'Not provided'
           },
           actions: {
             items