Thanks. Tried it and it doesnt like XP unless U run an old version (work that out!!!???). Anyway it refers me to an alternative called Filedisk which SHOULD do exactly what I want (although you do have to "install" it by copying a SYS file into Windows/System32/Drivers which I would rather not have to do).
I'm sure EVENTUALLY I'll find the exact tool.
I've had to email the Filedisk author as the tool does not work for me for some reason!??!?!