Thank you but I think I'll wait until My Son in Law can call round, Draclvr
I've found I can still "eventually" change wallpapers if I browse to My Pictures once I'm in the Display Properties box.
It's just a much more long-winded route than having them all already there
in the box to scroll through as they were before.
The only "different" thing I've done, from when the situation was normal to how it is now, is download The Dark Eye game from The Adventure Shop.
But I can't see why doing that should have impacted on my wallpaper access