fix broken link

_includes/footer.html

 <footer class="site-footer">
   <p>&copy; {{ site.time | date: "%Y" }} {{ site.copyright }}<br />
-  <a href="https://www.imperial.ac.uk/about-the-site/privacy/">Privacy Notice</a> - <a href="/accessibility">Accessibility</a></p>
+  <a href="https://www.imperial.ac.uk/about-the-site/privacy/">Privacy Notice</a> - <a href="{{ '/accessibility/' | relative_url }}">Accessibility</a></p>
 </footer>

accessibility/accessibility.md

@@ -44,7 +44,7 @@ The content that is not accessible is outlined with details of:
 - where it fails the success criteria 
 - planned dates for when issues will be fixed
  
-[View our current list of non accessible content](/accessibility/non-accessible-list)
+[View our current list of non accessible content]({{ '/accessibility/non-accessible-list/' | relative_url }})
 
 Some documents and content are [exempt from the regulations](https://www.legislation.gov.uk/uksi/2018/952/regulation/4/made) (such as live video content and PDFs or other documents published before 23 September 2018 if they’re not essential to providing our services), so we do not currently have any plans to make them accessible. But if you need to access information in one of these document types, you can contact us and ask for an alternative format.