diff --git a/docs/schemas/2024-10/donor-details.json b/docs/schemas/2024-10/donor-details.json
index 2d49ca16..7d7de03a 100644
--- a/docs/schemas/2024-10/donor-details.json
+++ b/docs/schemas/2024-10/donor-details.json
@@ -9,7 +9,8 @@
     "donor",
     "attorneys",
     "certificateProvider",
-    "signedAt"
+    "signedAt",
+    "witnessedByCertificateProviderAt"
   ],
   "properties": {
     "lpaType": {
diff --git a/internal/validate/validate.go b/internal/validate/validate.go
index 89f70168..6c9157eb 100644
--- a/internal/validate/validate.go
+++ b/internal/validate/validate.go
@@ -75,8 +75,8 @@ func Date(source string, date shared.Date) []shared.FieldError {
 	return nil
 }
 
-func Time(source string, t time.Time) []shared.FieldError {
-	return If(t.IsZero(), []shared.FieldError{{Source: source, Detail: "field is required"}})
+func Time(source string, t interface{ IsZero() bool }) []shared.FieldError {
+	return If(t == (*time.Time)(nil) || t.IsZero(), []shared.FieldError{{Source: source, Detail: "field is required"}})
 }
 
 func OptionalTime(source string, t *time.Time) []shared.FieldError {
diff --git a/lambda/create/validate.go b/lambda/create/validate.go
index 1cfe0c61..d4a6fab0 100644
--- a/lambda/create/validate.go
+++ b/lambda/create/validate.go
@@ -47,7 +47,8 @@ func Validate(lpa shared.LpaInit) []shared.FieldError {
 				validate.Required("/independentWitness/firstNames", lpa.IndependentWitness.FirstNames),
 				validate.Required("/independentWitness/lastName", lpa.IndependentWitness.LastName),
 				validate.Required("/independentWitness/phone", lpa.IndependentWitness.Phone),
-				validate.Address("/independentWitness/address", lpa.IndependentWitness.Address))
+				validate.Address("/independentWitness/address", lpa.IndependentWitness.Address),
+				validate.Time("/witnessedByIndependentWitnessAt", lpa.WitnessedByIndependentWitnessAt))
 		}),
 		validate.IfElse(activeAttorneyCount > 1,
 			validate.IsValid("/howAttorneysMakeDecisions", lpa.HowAttorneysMakeDecisions),
@@ -73,8 +74,7 @@ func Validate(lpa shared.LpaInit) []shared.FieldError {
 			validate.IsValid("/whenTheLpaCanBeUsed", lpa.WhenTheLpaCanBeUsed),
 			validate.Unset("/lifeSustainingTreatmentOption", lpa.LifeSustainingTreatmentOption))),
 		validate.Time("/signedAt", lpa.SignedAt),
-		// validate.Time("/witnessedByCertificateProviderAt", lpa.WitnessedByCertificateProviderAt),
-		// validate.OptionalTime("/witnessedByIndependentWitnessAt", lpa.WitnessedByIndependentWitnessAt),
+		validate.Time("/witnessedByCertificateProviderAt", lpa.WitnessedByCertificateProviderAt),
 		validate.OptionalTime("/certificateProviderNotRelatedConfirmedAt", lpa.CertificateProviderNotRelatedConfirmedAt),
 	)
 }
diff --git a/lambda/create/validate_test.go b/lambda/create/validate_test.go
index 92983997..bf69cc5b 100644
--- a/lambda/create/validate_test.go
+++ b/lambda/create/validate_test.go
@@ -213,7 +213,7 @@ func TestValidateLpaInvalid(t *testing.T) {
 				{Source: "/certificateProvider/phone", Detail: "field is required"},
 				{Source: "/attorneys", Detail: "at least one attorney is required"},
 				{Source: "/signedAt", Detail: "field is required"},
-				// {Source: "/witnessedByCertificateProviderAt", Detail: "field is required"},
+				{Source: "/witnessedByCertificateProviderAt", Detail: "field is required"},
 			},
 		},
 		"online certificate provider missing email": {
@@ -496,6 +496,24 @@ func TestValidateLpaInvalid(t *testing.T) {
 				{Source: "/donor/identityCheck/type", Detail: "invalid value"},
 			},
 		},
+		"independent witness missing witnessed at": {
+			lpa: func() shared.LpaInit {
+				lpa := makeLpaWithDonorAndActors()
+				lpa.IndependentWitness = &shared.IndependentWitness{
+					Person: shared.Person{
+						UID:        "b99af83d-5b6c-44f7-8c03-14004699bdb9",
+						FirstNames: "Some",
+						LastName:   "Person",
+					},
+					Address: validAddress,
+					Phone:   "077777",
+				}
+				return lpa
+			},
+			expectedErrors: []shared.FieldError{
+				{Source: "/witnessedByIndependentWitnessAt", Detail: "field is required"},
+			},
+		},
 	}
 
 	for name, tc := range testcases {
diff --git a/mock-apigw/main.go b/mock-apigw/main.go
index abab9eec..a8756417 100644
--- a/mock-apigw/main.go
+++ b/mock-apigw/main.go
@@ -184,6 +184,7 @@ func handlePactState(r *http.Request) error {
 			},
 			"lifeSustainingTreatmentOption": "option-a",
 			"signedAt": "2000-01-02T12:13:14Z",
+			"witnessedByCertificateProviderAt": "2000-01-02T13:13:14Z",
 			"howAttorneysMakeDecisions": "jointly"
 		}`