diff --git a/src/components/Organisms/MarketingPreferencesDS/MarketingPreferencesDSForm.js b/src/components/Organisms/MarketingPreferencesDS/MarketingPreferencesDSForm.js
index 99834eaab..f3f9c1ebc 100644
--- a/src/components/Organisms/MarketingPreferencesDS/MarketingPreferencesDSForm.js
+++ b/src/components/Organisms/MarketingPreferencesDS/MarketingPreferencesDSForm.js
@@ -1,4 +1,5 @@
-import React from 'react';
+/* eslint-disable no-console */
+import React, { useState } from 'react';
 import { useForm, FormProvider } from 'react-hook-form';
 import { yupResolver } from '@hookform/resolvers/yup';
 import Text from '../../Atoms/Text/Text';
@@ -23,7 +24,8 @@ const { mpValidationSchema, mpValidationOptions } = mpValidation;
 
 // Or customise and override the config to suit the destination app's requirements:
 const initalValueOverrides = {
-  mp_email: 'user@website.com' // Potentially provided earlier in the journey
+  mp_email: 'user@website.com', // Potentially provided earlier in the journey
+  mp_permissionEmail: 'true'
 };
 const validationOverrides = {
   mp_permissionEmail: { hideInput: true }, // As we're passing a value above, hide the user input
@@ -41,9 +43,12 @@ const {
 } = mpValidationCustom;
 
 const MarketingPreferencesDSForm = () => {
+  const [emailInteractedWith, setEmailInteractedWith] = useState(false);
+
   function customSubmitHandler(formData) {
-    // eslint-disable-next-line no-console
+    // Obviously, in a *real* context, we'd do something useful with this data:
     console.log('Successful submission', formData);
+    console.log('emailInteractedWith:', emailInteractedWith);
   }
 
   // For our default instance:
@@ -71,6 +76,8 @@ const MarketingPreferencesDSForm = () => {
             mpValidationOptions={mpValidationOptions}
             id="default"
             formContext={formMethods}
+            // Directly pass in our useState 'set' function as the callback:
+            emailInteractedCallback={setEmailInteractedWith}
           />
           <input type="submit" />
         </form>
@@ -85,6 +92,8 @@ const MarketingPreferencesDSForm = () => {
             mpValidationOptions={mpValidationOptionsCustom}
             id="custom"
             formContext={formMethodsCustom}
+            // Directly pass in our useState 'set' function as the callback:
+            emailInteractedCallback={setEmailInteractedWith}
           />
           <input type="submit" />
         </form>
diff --git a/src/components/Organisms/MarketingPreferencesDS/_MarketingPreferencesDS.js b/src/components/Organisms/MarketingPreferencesDS/_MarketingPreferencesDS.js
index 33e8a34e2..b62aeae3e 100644
--- a/src/components/Organisms/MarketingPreferencesDS/_MarketingPreferencesDS.js
+++ b/src/components/Organisms/MarketingPreferencesDS/_MarketingPreferencesDS.js
@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { useEffect } from 'react';
 import PropTypes from 'prop-types';
 import { useWatch } from 'react-hook-form';
 import _ from 'lodash';
@@ -20,6 +20,7 @@ const MarketingPreferencesDS = ({
   mpValidationOptions,
   id = null,
   formContext = null,
+  emailInteractedCallback,
   ...rest
 }) => {
   const { formState: { errors }, control } = formContext;
@@ -30,6 +31,14 @@ const MarketingPreferencesDS = ({
   const phoneChoice = useWatch({ control, name: 'mp_permissionPhone', defaultValue: null });
   const smsChoice = useWatch({ control, name: 'mp_permissionSMS', defaultValue: null });
 
+  useEffect(() => {
+    // Don't run on initial mount, only when actually updated:
+    if (emailChoice !== null) {
+      // Fire callback to update flag in parent component:
+      emailInteractedCallback(true);
+    }
+  }, [emailChoice, emailInteractedCallback]);
+
   const {
     // eslint-disable-next-line camelcase
     mp_permissionEmail, mp_permissionSMS, mp_permissionPhone, mp_permissionPost
@@ -37,11 +46,8 @@ const MarketingPreferencesDS = ({
 
   // If the field is not required for each No/Yes choice, remove it from the DOM entirely
   const disableEmailInput = (mp_permissionEmail.yes === false && emailChoice.includes('yes'));
-
   const disableSMSInput = (mp_permissionSMS.yes === false && smsChoice.includes('yes'));
-
   const disablePhoneInput = (mp_permissionPhone.yes === false && phoneChoice.includes('yes'));
-
   const disablePostInput = (mp_permissionPost.yes === false && postChoice.includes('yes'));
 
   // Required to track multiple errors to determine whether to show/hide the fieldset
@@ -273,7 +279,9 @@ MarketingPreferencesDS.propTypes = {
   in the parent to set-up the validation, but also required here for additional functionality */
   mpValidationOptions: PropTypes.objectOf(PropTypes.shape).isRequired,
   id: PropTypes.string,
-  formContext: PropTypes.shape()
+  formContext: PropTypes.shape(),
+  // For soft opt-in, as react-hook-form's 'isDirty' doesn't work with checkboxes, only Fields 😮‍💨
+  emailInteractedCallback: PropTypes.func
 };
 
 MaybeDisabled.propTypes = {
diff --git a/src/components/Organisms/MarketingPreferencesDS/_MarketingPrefsConfig.js b/src/components/Organisms/MarketingPreferencesDS/_MarketingPrefsConfig.js
index dc9ec76bd..555a29550 100644
--- a/src/components/Organisms/MarketingPreferencesDS/_MarketingPrefsConfig.js
+++ b/src/components/Organisms/MarketingPreferencesDS/_MarketingPrefsConfig.js
@@ -1,6 +1,8 @@
 import * as yup from 'yup';
 import { merge } from 'lodash';
 
+const phoneRegex = /^(((((\+44)|(0044))\s?\d{4}|\(?0\d{4}\)?)\s?\d{3}\s?\d{3})|((((\+44)|(0044))\s?\d{3}|\(?0\d{3}\)?)\s?\d{3}\s?\d{4})|((((\+44)|(0044))\s?\d{2}|\(?0\d{2}\)?)\s?\d{4}\s?\d{4}))(\s?\\#(\d{4}|\d{3}))?$/;
+
 const setInitialValues = overrideValues => {
   const defaultValues = {
     mp_email: '',
@@ -61,8 +63,6 @@ const buildValidationSchema = overrideOptions => {
   // Override with any custom options supplied
   const mpValidationOptions = merge(defaultOptions, overrideOptions);
 
-  const phoneRegex = /^(((((\+44)|(0044))\s?\d{4}|\(?0\d{4}\)?)\s?\d{3}\s?\d{3})|((((\+44)|(0044))\s?\d{3}|\(?0\d{3}\)?)\s?\d{3}\s?\d{4})|((((\+44)|(0044))\s?\d{2}|\(?0\d{2}\)?)\s?\d{4}\s?\d{4}))(\s?\\#(\d{4}|\d{3}))?$/;
-
   const mpValidationFields = {
     mp_email: yup.string()
       .when('mp_permissionEmail', {