I've got no problems locking into the Satellites, but I frequently lose position when I'm off a main road, and get a warning that the map isn't reliable for navigation. Sometimes the set up loses lock whilst I'm driving on an outback road, and it hunts around for a while until it finds the road again, and sorts itself out.

Since I live in the Alps during winter, and the moment I get off the main Alpine Way onto the side streets of the village, it loses itself, this comes under the heading of Really Irritating. It's always by about 150 - 200 metres: does anyone else have a similar problem?