I have managed almost 2 days without any problems.

Today however I needed to use the sat nav and although I left it on for nearly an hour, it seems no GPS signal is reaching the sat nav system as the map is all aver the place and cannot identify my position.

I gather some fault with the aerial but although it's been a few months since I last used it, the one thing that is different is that I swapped out the old telephone control unit for a bluetooth one recently. I originally thought this would be totally separate but in another forum, it is mentioned the sat nav uses this box !

Can anyone help with advice or circuit diagram ? 2002 Vogue 4.4 V8
1995 Disco 1 300tdi

The usual reason for loss of GPS signal is corrosion of the aerial/connectiuons to the aerial, or you're still in the garage.
If it's of any help to you, I can email you your complete vehicle wiring diagrams if you pm me your email address.

Tearing my hair out a wee bit with this thing. I am beginning to think the bluetooth upgrade is into the problem. Although the sat nav is connected to the b/t module, it's also connected just about everything else as well and of course lots on this forum have done the upgrade and no ones mentioned losing their sat nav.

So back to basics, the Lh boot area is bone dry, all the connections appear good so have a look at the antenna. I guess this is it on the right But how to test without buying another one. Any ideas ?

Just a thought before you go and buy a new aerial.
Are you certain the correct aerial lead is connected into the Navigation Module?
Unfortunately the tv aerial leads are the same cable and plugs as the navigation lead.
It has been known for the wrong lead to be plugged into navigation module with the obvious loss of gps function.

All cables checked and correct. The price of a new aerial is over £130 so kind of stuck what to do now. I had a look at the settings as described in the workshop manual and this is what it shows