So if its of any use to anyone this is what i did
1 installed setup disc
2 installed v6 city select Mapsource( the one that came with the unit)
3 registered the unit ( it asks you to do this during the setup procedure)
4 installed v8 city navigator ( this is where it asked for the unlock code and i tried the original one and it said they were unlocked )
5 Found that when i opened up Mapsource the maps were still unlocked
6 Went to
http://www.garmin.com/
7 Clicked on "SUPPORT"
http://www.garmin.com/
8 Clicked on "Mapsource unlock" in the left hand column
9 selected language
10 put in the 7 digit registration code in the "returning customer " box
11 This page told me when the unit was registered and that i was elligible for a free update
12 Clicked on " unlock update disc" and it generated a new code for me
13 Opened up Mapsource on the pc and and clicked on the unlock map details box (bottom right hand of screen)copied and pasted new code
and the fecker worked