Everything was fine in native Windows except I had to re-activate Windows again (Office activation had been kept though).
When I rebooted into the BC VM, Windows and Office were still activated, but the tray area took a while to populate and didn't do fully, as if there was a problem with one of the apps. After rebooting back into the BC VM, everything was perfect.
Finally, I rebooted back into native Windows again and both Windows and Office were still activated.
The only issue I'm having is that after using native Windows, I find the clock is one hour ahead when I boot back into OSX. the is no such problem after using the BC VM though. As I understand it, Apple stores the time in GMT rather than BST in the BIOS/UEFI, and OSX adjusts it for BST. OTOH, Windows based PC's store the time as-is in the BIOS/UEFI (ie. in GMT or BST). Boot Camp has a time service for Windows that is supposed to handle this time issue transparently, but it doesn't appear to be working in my case.
I normally run as a standard user in Windows and noticed that the BootCamp display brightness level wasn't being remembered in native Windows between reboots. When I logged in as admin and set the level, it was remembered. Oddly, the other two BC settings for F1, F2 keys and trackpad were remembered under SUA. It's possible this is why the time service isn't working correctly.
The other thing I noticed is that CPU usage is very high after logging in, while all the startup programs are launching. I guess this is partly due to running in a VM, although I hope general performance and rawdisk performance can be improved in later versions of Fusion (eg. 5).
Just need to sort out this time issue and I'll be sorted.