Hi Guy's,
As you can see I am new to this so please be patient I have had trouble locating the maps on my Garmin Nuvi 1390 until today here is how you find them :-
1: Connect the Garmin to the PC
2: Go to my Computer and double click on Garmin
3: Top left hand corner you will see Organise click on it
4: Locate folder and search options click on it
5: Click on View
6: Click on show hidden files, folders and drives
7: UN TICK hide protected operating system files and Viola then you have access to your hidden maps.

" MAKE SURE YOU REVERSE THE ACTIONS YOU HAVE TAKEN ONCE THE GARMIN IS FINNISHED YOU HAVE BEEN WARNED "