In reply to tnj: Why don't you use another mapping provider such as www.mapyx.com. You can download that for free and use the opensource mapping (which I find excellent) also for free. You can then download your waypoints, trips, etc; save them as a .gpx file and reload them into Mapsource if you have any other mapping. The opensouce mapping really is very good, although the mapyx software won't allow you to upload the maps with contour sets. You can then download a full set of GPS waypoints for all your UK mountain tops onto the mapyx for reference. Hope that helps.
Dave
cgruk.co.uk
follow me on twitter @cgruk