Hi,
The restore issue is now resolved. There was an underlying issue which a Symantec engineer pointed out which is that restore selection lists can become corrupt so although it looked correct on the screen, it was corrupt in the database.
While the engineer went off to see what else was causing the main issue I managed to solve it. The issue with restoring was due to there not being a user account on the backup server with the same name and password as the one created on the vSphere server. Again, even though in the GUI everything checked out and credentials were validated, BE required a Windows user (member of local admins) to exist on the local server.
At the main site you can add the backup service account to vCenter and grant permissions. At the recovery site without vCenter you can't do this as vSphere can't have a Windows user account in the format domain\username. Therefore I created a vSphere user and a local Windows user with the same name, problem solved!
All of this is documented BUT it is easy to mistake the vSphere credentials you supply for restore redirection and for BE to browse the vSphere server as being what is required. All that does is connect you to the resources which misleads you into thinking you've done everything correctly. The key is to use the right username, not just one that will connect you to vSphere, it needs to be one that you have created on the BE server to run the services under and also created on vSphere and granted the required permissions - the two are "tied" together. You can create two accounts if you prefer but I don't see the need to.
Restores are now working as they should be, albeit a bit on the slow side (600MB/min). I will try 2012 and see if the SAN option for restore is there.