Thanks for that Brink. Before I try restoring and recreating, I'd like to know why these extra folders have appeared. I've attempted more than once to move the folders (restoring back to a known install point) and it's happened each time - so I assume if I restore the original location and recreate the same thing is going to happen.
As I mentioned, the three rogue folders are sort of duplicates of the My Music, My Pictures, and Videos folders (called Music, Pictures and Videos). These folders don't have the location tab. The relocated folders appear to work correctly (the location tab points to the right place and opens them correctly.
So the main question is whether I can simply delete the duplicate folders (and if I can, how can I do it since it tells me I don't have permission). I suppose what I need to know is will windows being registering the folders in any way - for example, I now appear to have two folders called Videos (I suppose one is a "proper" folder and the other is some sort of shortcut) so will it be registering them differently.