For those taking an interest in my wife's journey with Windows 8...
In the end we did a full wipe and refresh and started again, this time using the email address that she wanted. It's going much better this time round, without the frustrations with pop-ups and login issues we were getting before - though we're more familiar with how things work, of course.
We had to go through the several hours of updates again, and haven't yet installed her MS Office suite, but she's got to grips with the home screen and store apps. We are having difficulty with our printer though (a recent LaserJet). The installation proceeds fine but right at the end says that it couldn't install.
One more good session on this and she should be ready to use it for work. She's said that now she's got her head round it she thinks she's really going to like it.
Graham