diff --git a/src/middleware/dataview.middleware.js b/src/middleware/dataview.middleware.js
index 71f424eda..2a520de50 100644
--- a/src/middleware/dataview.middleware.js
+++ b/src/middleware/dataview.middleware.js
@@ -8,6 +8,7 @@ import {
   fetchLocalPlanningGroups,
   fetchProvisionsByOrgsAndDatasets,
   fetchOrgInfo,
+  fetchSources,
   noop,
   processAuthoritativeMiddlewares,
   processSpecificationMiddlewares,
@@ -92,7 +93,11 @@ const fetchOutOfBoundsExpectations = expectationFetcher({
 })
 
 export const prepareTemplateParams = (req, res, next) => {
-  const { orgInfo, dataset, tableParams, pagination, dataRange, tasks, authority, alternateSources, uniqueDatasetFields, provisions, expectationOutOfBounds } = req
+  const { orgInfo, dataset, tableParams, pagination, dataRange, tasks, authority, alternateSources, uniqueDatasetFields, provisions, expectationOutOfBounds, sources } = req
+
+  // Match the overview page: 'some' authority uses alternative/pre-populated
+  // sources, not the LPA's own endpoints, so it reports no endpoints.
+  const endpointCount = authority === 'some' ? 0 : (sources?.length ?? 0)
 
   const outOfBoundsCount = (expectationOutOfBounds?.length ?? 0) > 0 ? 1 : 0
   const taskCount = authority !== 'some' ? (tasks?.count ?? 0) + outOfBoundsCount : 1
@@ -112,6 +117,7 @@ export const prepareTemplateParams = (req, res, next) => {
     authority,
     dataset,
     taskCount,
+    endpointCount,
     tableParams,
     pagination,
     dataRange,
@@ -138,6 +144,7 @@ export default [
   fetchDatasetInfo,
 
   fetchResources,
+  fetchSources,
   fetchTasksFromPlatformApi,
   isFeatureEnabled('expectationOutOfBoundsTask') ? fetchOutOfBoundsExpectations : noop,
 
diff --git a/src/routes/schemas.js b/src/routes/schemas.js
index e263badcf..2eb625150 100644
--- a/src/routes/schemas.js
+++ b/src/routes/schemas.js
@@ -213,6 +213,7 @@ export const OrgDataView = v.strictObject({
   organisation: OrgField,
   dataset: DatasetNameField,
   taskCount: v.integer(),
+  endpointCount: v.integer(),
   authority: v.string(),
   tableParams,
   pagination: PaginationParams,
diff --git a/src/views/organisations/dataset-overview.html b/src/views/organisations/dataset-overview.html
index 28f5335d0..4caf081cc 100644
--- a/src/views/organisations/dataset-overview.html
+++ b/src/views/organisations/dataset-overview.html
@@ -213,7 +213,7 @@ <h2 class="govuk-heading-m">Dataset details</h2>
     {% if authority !== 'some' %}
     <section>
       <h2 class="govuk-heading-m">Active endpoints</h2>
-      <p class="govuk-body">You have {{ endpointCount }} endpoint{% if endpointCount != 1 %}s{% endif %} we are currently checking for data.</p>
+      <p class="govuk-body">You have {{ endpointCount }} endpoint{% if endpointCount != 1 %}s{% endif %} we are currently checking for data.{% if endpointCount > 1 %} The information within dataset details includes data from all {{ endpointCount }} endpoints.{% endif %}</p>
       {% for endpointSummaryCard in endpointSummaryCards %}
         {{ govukSummaryList(endpointSummaryCard) }}
       {% endfor %}
diff --git a/src/views/organisations/dataview.html b/src/views/organisations/dataview.html
index a1d82125b..5ef5efb36 100644
--- a/src/views/organisations/dataview.html
+++ b/src/views/organisations/dataview.html
@@ -59,6 +59,18 @@
   </div>
 </div>
 
+<div class="govuk-grid-row">
+  <div class="govuk-grid-column-two-thirds">
+    <section>
+      <h2 class="govuk-heading-m">About this data</h2>
+      <p class="govuk-body">We accept data in different formats and standardise it, so that we can combine it with data from other sources. This means the data we show might be in a different format to the data you provided. For example, we standardise all dates as YYYY-MM-DD.</p>
+      {% if endpointCount > 1 %}
+        <p class="govuk-body">The information within this data is from all {{ endpointCount }} of your endpoints.</p>
+      {% endif %}
+    </section>
+  </div>
+</div>
+
 <div class="govuk-grid-row">
   <div class="govuk-grid-column-full">
     {{ table(tableParams) }}
diff --git a/test/acceptance/request_check.test.js b/test/acceptance/request_check.test.js
index 2896c2c7e..103e364d8 100644
--- a/test/acceptance/request_check.test.js
+++ b/test/acceptance/request_check.test.js
@@ -21,8 +21,7 @@ const navigateToCheck = async (page) => {
 
 const okFile = 'https://raw.githubusercontent.com/digital-land/PublishExamples/refs/heads/main/Article4Direction/Files/Article4DirectionArea/article4directionareas-ok.csv'
 const errorFile = 'https://raw.githubusercontent.com/digital-land/PublishExamples/refs/heads/main/Article4Direction/Files/Article4DirectionArea/article4directionareas-errors.csv'
-// TODO: this file should cause a SSL Certificate error when served to the async. It currently does but is temporary (A link that causes a Server Timeout Error or SSL Error is required)
-const serverErrorFile = 'https://www.tendringdc.gov.uk/sites/default/files/documents/planning/CAD%20csv.csv'
+const serverErrorFile = 'http://expired.badssl.com'
 const htmlFile = 'https://en.wikipedia.org/wiki/John_Doe'
 
 let lastTimestamp = 0
diff --git a/test/unit/middleware/dataview.middleware.test.js b/test/unit/middleware/dataview.middleware.test.js
index 1bd515852..77ad1b948 100644
--- a/test/unit/middleware/dataview.middleware.test.js
+++ b/test/unit/middleware/dataview.middleware.test.js
@@ -206,6 +206,7 @@ describe('dataview.middleware.test.js', () => {
         dataset: { name: 'Mock Dataset', dataset: 'mock-dataset' },
         authority: 'mock-authority',
         taskCount: 0,
+        endpointCount: 0,
         tableParams: { columns: ['foo'], fields: ['foo'] },
         pagination: {},
         dataRange: {