My Amundsen Sat Nav has suddenly developed a fault. On turning on, the Škoda Navigation logo is no longer shown and the screen is plain with direction arrow but no map. Accepts input for a destination but is "frozen" to a destination point which is not selected and in the "extras" screen, shows SE England in very basic mapping mode and route detail lists "frozen" destination. All other functions of the Amundsen seem to be working ok.

I have tried resolve with factory reset. Is there any other action I can try ? Will I need to reinstall the mapping software ? I have seen SD cards advertised for Western Europe, will the use of these cards overwrite existing data and resolve my problem. Or is this a main dealer job.

Any advice would be very much appreciated.

The only thing I can think of is that the antenna has an issue. I had similar problems with my 315 showing me being in the channel. after a few weeks without my nav I realised there was water bubbling from under the antenna where it meets the roof when I moved it about I took the lining back on the roof to check out the connections. my antenna on had somehow come a little loose and had a fair bit of water in there, luckily it hadn't gone through to the lining. I cleaned everything up, tightened it up and it sorted itself out. I now have the 510 so I can't give much help if it is a software issue. 

Thanks Daz1412. I checked the antenna but found no possible cause as the fixture/seal on roof has no movement or obvious water leak. Radio reception is excellent. I am wondering whether there is a separate antenna for the GP ?

The GPS antenna is in the base of the roof antenna, which is also the FM antenna. It's not uncommon for the antenna to suffer from water ingress or failure. Somewhere in the menu there's a page where the number of satellites seen and locked onto is detailed, check and see what that says first.