Thank you all for your help. I went back through the WET process and I think that when I came to the "Choose what to transfer to this computer
" step I clicked on Advanced Options in the bottom RH corner which takes you to the "Map user accounts
" screen. I think I then clicked the drop down menu and created new user accounts in the same name as the old.
My recollection is a bit hazy (well, it was about 2.30 am at the time!), but I suspect that in doing so I must have told Windows simply to transfer the documents into folders bearing the names of the users instead of letting Windows set up the user accounts itself and transferring all the files and settings itself!
I've deleted the user folders that were created and run WET again, this time not mapping user accounts, and it has worked, including all e-mail settings. Hooray!
There are still a few minor glitches with the names of the user folders, namely that where a couple of the user names were renamed in Vista a couple of years ago, the old user folder names have carried over to the new set up, which is a bit frustrating. I guess I could do as gregrocker and DustSailor suggest (and as has been suggested elsewhere) and set up new user accounts and copy the data over. But how would I copy over the email/contacts/calendar data? I can't see it in the user folder, unless of course they're hidden files. Any suggestions?