Nav+ problems (RNS-D)

[carrotchomper]

Folks,

This is very annoying. The Nav+ unit in my PF D2 ('98) works perfectly... Apart from the Nav

When I bought the car down in Somerset, the unit was locked, as the battery had been flat. Finally found the code, and tried the Nav- It worked fine, showed current location correctly and when set to navigate to Bristol showed the correct-ish route and distance.

I obviously didn't use it then as I know the way! Since then I have needed to use it a couple of times, and the GPS constantly thinks it is somewhere near Poole. It will accept a destination, but obviously won't navigate there- On the "Lat/Lon" display it constantly shows what I believe is a default...

...This is doubly annoying because my little Garmin portable Nav unit has ceased to pick up satellites for some unknown reason

It has the most up-to-date Nav CD in it (2005?) which I think you can get for mine...

Help!