If you can find the access denied page in the EPiServer install location you can add a URL mapping in web.config (<system.web> <urlMappings> <url url="installlocation" mappedUrl="custom file">)
I hope this helps,
Default behavior is to return the login page, you can however override the AccessDenied method and implement your own logic.
Hope this helps.
Many thanks both.
More than enough to go on!
Is there anyway of customizing the page that appears when a user logs in, and it says...
You do not have sufficient rights to view this page.
Does it sit somewhere in the EPiServer directory?