diff --git a/src/controllers/CheckAnswersController.js b/src/controllers/CheckAnswersController.js
index 2749fe03..4034f806 100644
--- a/src/controllers/CheckAnswersController.js
+++ b/src/controllers/CheckAnswersController.js
@@ -10,7 +10,8 @@ import { getDatasets } from '../utils/utils.js'
 class CheckAnswersController extends PageController {
   async locals (req, res, next) {
     const requestId = req.sessionModel.get('requestId')
-    if (!requestId) {
+    const dataset = req.sessionModel.get('dataset')
+    if (!requestId || !dataset) {
       return res.redirect('/check/url')
     }
     try {
diff --git a/src/controllers/datasetDetailsController.js b/src/controllers/datasetDetailsController.js
index 7a39983e..808ee3b7 100644
--- a/src/controllers/datasetDetailsController.js
+++ b/src/controllers/datasetDetailsController.js
@@ -3,7 +3,8 @@ import PageController from './pageController.js'
 class DatasetDetailsController extends PageController {
   locals (req, res, next) {
     const requestId = req.sessionModel.get('requestId')
-    if (!requestId) {
+    const dataset = req.sessionModel.get('dataset')
+    if (!requestId || !dataset) {
       return res.redirect('/check/url')
     }
     super.locals(req, res, next)
diff --git a/src/controllers/lpaDetailsController.js b/src/controllers/lpaDetailsController.js
index 85c4b6a3..cb488428 100644
--- a/src/controllers/lpaDetailsController.js
+++ b/src/controllers/lpaDetailsController.js
@@ -9,11 +9,11 @@ class LpaDetailsController extends PageController {
 
     try {
       const requestData = await getRequestData(requestId)
-      if (requestData?.getParams()?.type !== 'check_url') {
+      const params = requestData?.getParams()
+      if (params?.type !== 'check_url' || !params.dataset) {
         return res.redirect('/check/url')
       }
       // Populate submit wizard session from the check request params
-      const params = requestData.getParams()
       const orgId = params.organisationName
       req.sessionModel.set('requestId', requestId)
       req.sessionModel.set('lpa', orgIdToName(orgId))
@@ -33,7 +33,7 @@ class LpaDetailsController extends PageController {
       value: name
     }))
 
-    req.form.options.lastPage = `/check/results/${req.session.checkRequestId}/1`
+    req.form.options.lastPage = `/check/results/${requestId}/1`
 
     super.locals(req, res, next)
   }
diff --git a/src/controllers/pageController.js b/src/controllers/pageController.js
index 30ba1d39..3f08c868 100644
--- a/src/controllers/pageController.js
+++ b/src/controllers/pageController.js
@@ -79,10 +79,12 @@ class PageController extends Controller {
     }
 
     const dataset = req?.sessionModel?.get('dataset')
-    try {
-      req.form.options.datasetName = datasetSlugToReadableName(dataset)
-    } catch (e) {
-      logger.warn(`Failed to get readable dataset name from slug: ${dataset}`)
+    if (dataset) {
+      try {
+        req.form.options.datasetName = datasetSlugToReadableName(dataset)
+      } catch (e) {
+        logger.warn(`Failed to get readable dataset name from slug: ${dataset}`)
+      }
     }
 
     const errors = req?.sessionModel?.get('errors')
diff --git a/src/filters/makeDatasetSlugToReadableNameFilter.js b/src/filters/makeDatasetSlugToReadableNameFilter.js
index d99b3dcd..49def78b 100644
--- a/src/filters/makeDatasetSlugToReadableNameFilter.js
+++ b/src/filters/makeDatasetSlugToReadableNameFilter.js
@@ -20,6 +20,11 @@ export const makeDatasetSlugToReadableNameFilter = (datasetNameMapping) => {
   const lowercaseFirst = (str) => str.charAt(0).toLowerCase() + str.slice(1)
 
   return (slug, capitalize = false) => {
+    if (!slug) {
+      logger.debug(`can't find a dataset name for ${slug}`)
+      return slug
+    }
+
     const name = datasetNameMapping.get(slug)
     if (!name) {
       // ToDo: work out what to do here? potentially update it with data from datasette
diff --git a/test/unit/PageController.test.js b/test/unit/PageController.test.js
index 9a767ecb..b6076cc1 100644
--- a/test/unit/PageController.test.js
+++ b/test/unit/PageController.test.js
@@ -128,9 +128,11 @@ describe('PageController', () => {
     })
 
     it('handles missing dataset gracefully', () => {
-      req.sessionModel.get.mockReturnValue({})
+      vi.clearAllMocks()
+      req.sessionModel.get.mockReturnValue(undefined)
       pageController.locals(req, {}, vi.fn())
       expect(req.form.options.datasetName).toBeUndefined()
+      expect(datasetSlugToReadableName.datasetSlugToReadableName).not.toHaveBeenCalled()
     })
 
     it('handles datasetSlugToReadableName errors gracefully', () => {
diff --git a/test/unit/checkAnswersController.test.js b/test/unit/checkAnswersController.test.js
index a22734bf..a0fc7f32 100644
--- a/test/unit/checkAnswersController.test.js
+++ b/test/unit/checkAnswersController.test.js
@@ -37,6 +37,20 @@ describe('CheckAnswersController', () => {
     vi.clearAllMocks()
   })
 
+  describe('locals', () => {
+    it('should redirect to /check/url when dataset is missing', async () => {
+      req.sessionModel.get.mockImplementation(key => ({
+        requestId: 'existing-request-id'
+      }[key]))
+
+      await controller.locals(req, res, next)
+
+      expect(res.redirect).toHaveBeenCalledWith('/check/url')
+      expect(getRequestData).not.toHaveBeenCalled()
+      expect(next).not.toHaveBeenCalled()
+    })
+  })
+
   describe('POST to CheckAnswersController', () => {
     it('should create a Jira issue and set session data on success', async () => {
       const issue = { issueKey: 'TEST-123' }
diff --git a/test/unit/lpaDetailsController.test.js b/test/unit/lpaDetailsController.test.js
index ab8ad6a5..ea24903a 100644
--- a/test/unit/lpaDetailsController.test.js
+++ b/test/unit/lpaDetailsController.test.js
@@ -88,6 +88,17 @@ describe('lpaDetailsController', async () => {
       expect(next).not.toHaveBeenCalled()
     })
 
+    it('should redirect to /check/url when request params do not include a dataset', async () => {
+      getRequestData.mockResolvedValue({
+        getParams: () => ({ type: 'check_url', organisationName: 'Mock LPA' })
+      })
+
+      await controller.locals(req, res, next)
+
+      expect(res.redirect).toHaveBeenCalledWith('/check/url')
+      expect(next).not.toHaveBeenCalled()
+    })
+
     it('should redirect to /check/url when getRequestData throws', async () => {
       getRequestData.mockRejectedValue(new Error('API error'))
 
diff --git a/test/unit/makeDatasetSlugToReadableNameFilter.test.js b/test/unit/makeDatasetSlugToReadableNameFilter.test.js
index b97f164f..11d4afac 100644
--- a/test/unit/makeDatasetSlugToReadableNameFilter.test.js
+++ b/test/unit/makeDatasetSlugToReadableNameFilter.test.js
@@ -24,4 +24,11 @@ describe('makeDatasetSlugToReadableNameFilter', () => {
     expect(filter('Unknown-slug')).toBe('unknown-slug')
     expect(filter('Unknown-slug', true)).toBe('Unknown-slug')
   })
+
+  it('returns a missing slug without trying to capitalize it', () => {
+    expect(filter(undefined)).toBeUndefined()
+    expect(filter(undefined, true)).toBeUndefined()
+    expect(filter(null)).toBeNull()
+    expect(filter(null, true)).toBeNull()
+  })
 })