diff --git a/src/config/index.js b/src/config/index.js
index 1ff40ec..b7ce014 100644
--- a/src/config/index.js
+++ b/src/config/index.js
@@ -48,6 +48,7 @@ export const config = convict({
   cdpEnvironment: {
     doc: 'The CDP environment the app is running in. With the addition of "local" for local development',
     format: ['local', 'dev', 'test', 'perf-test', 'prod', 'ext-test'],
+    nullable: true,
     default: null,
     env: 'ENVIRONMENT'
   },
@@ -119,6 +120,7 @@ export const config = convict({
   httpsProxy: {
     doc: 'HTTPS Proxy',
     format: String,
+    nullable: true,
     default: null,
     env: 'CDP_HTTPS_PROXY'
   },
@@ -193,6 +195,7 @@ export const config = convict({
   oidcVerifyAud: {
     doc: 'The audience used for verifying the OIDC JWT',
     format: String,
+    nullable: true,
     default: null,
     env: 'OIDC_VERIFY_AUD'
   },
@@ -200,6 +203,7 @@ export const config = convict({
   oidcVerifyIss: {
     doc: 'The issuer used for verifying the OIDC JWT',
     format: String,
+    nullable: true,
     default: null,
     env: 'OIDC_VERIFY_ISS'
   },
@@ -207,6 +211,7 @@ export const config = convict({
   entitlementUrl: {
     doc: 'Forms entitlements API URL',
     format: String,
+    nullable: true,
     default: null,
     env: 'ENTITLEMENT_URL'
   },
@@ -215,6 +220,7 @@ export const config = convict({
     header: {
       doc: 'CDP tracing header name',
       format: String,
+      nullable: true,
       default: null,
       env: 'TRACING_HEADER'
     }
@@ -265,6 +271,7 @@ export const config = convict({
   sqsEventsDlqArn: {
     doc: 'SQS deadletter queue ARN',
     format: String,
+    nullable: true,
     default: null,
     env: 'EVENTS_SQS_DLQ_ARN'
   },
@@ -272,6 +279,7 @@ export const config = convict({
   fileExpiryInMonths: {
     doc: 'The number of months a file link is active for',
     format: Number,
+    nullable: true,
     default: null,
     env: 'FILE_EXPIRY_IN_MONTHS'
   }
diff --git a/src/service/mappers/user-confirmation.js b/src/service/mappers/user-confirmation.js
index acfcef8..587dadf 100644
--- a/src/service/mappers/user-confirmation.js
+++ b/src/service/mappers/user-confirmation.js
@@ -81,13 +81,13 @@ ${formattedAnswers}
 # Form submitted
 ${referenceNumber}We received your form submission for ‘${escapeContent(formName)}’ at ${formattedSubmissionDate}.
 ${paymentSection}
-## What happens next
+# What happens next
 ${submissionGuidance ?? submisionGuidancePlaceholder}
 
-## Get help
+# Get help
 ${contactDetails}
 
-## Your answers
+# Your answers
 Find a copy of your answers at the bottom of this email.
 
 Do not reply to this email. We do not monitor replies to this email address.
diff --git a/src/service/mappers/user-confirmation.test.js b/src/service/mappers/user-confirmation.test.js
index 1a62ffc..b30b6af 100644
--- a/src/service/mappers/user-confirmation.test.js
+++ b/src/service/mappers/user-confirmation.test.js
@@ -40,13 +40,13 @@ describe('user-confirmation', () => {
 
 We received your form submission for ‘My Form Name’ at 2:21pm on Tuesday 4 November 2025.
 
-## What happens next
+# What happens next
 Some submission guidance
 
-## Get help
+# Get help
 
 
-## Your answers
+# Your answers
 Find a copy of your answers at the bottom of this email.
 
 Do not reply to this email. We do not monitor replies to this email address.
@@ -74,13 +74,13 @@ From Defra
 # Form submitted
 We received your form submission for ‘My Form Name’ at 2:21pm on Tuesday 4 November 2025.
 
-## What happens next
+# What happens next
 Define this text in the 'What happens next' section of the form overview
 
-## Get help
+# Get help
 
 
-## Your answers
+# Your answers
 Find a copy of your answers at the bottom of this email.
 
 Do not reply to this email. We do not monitor replies to this email address.
@@ -155,10 +155,10 @@ From Defra
 # Form submitted
 We received your form submission for ‘My Form Name’ at 2:21pm on Tuesday 4 November 2025.
 
-## What happens next
+# What happens next
 Some submission guidance
 
-## Get help
+# Get help
 0121 123456789
 
 [our-email@test.com](mailto:our-email@test.com)
@@ -168,7 +168,7 @@ We will respond within 5 working days
 
 
 
-## Your answers
+# Your answers
 Find a copy of your answers at the bottom of this email.
 
 Do not reply to this email. We do not monitor replies to this email address.
@@ -300,7 +300,7 @@ From Defra
       const paymentIndex = result.indexOf(
         '# Your payment of £50.00 was successful'
       )
-      const whatHappensNextIndex = result.indexOf('## What happens next')
+      const whatHappensNextIndex = result.indexOf('# What happens next')
 
       expect(paymentIndex).toBeGreaterThan(submissionTextIndex)
       expect(paymentIndex).toBeLessThan(whatHappensNextIndex)