download http://www.openstreetmap.org/index.html?lat=55.95&lon=-3.19&zoom=11 area as an osm file by clicking on Export.

then using mkgmap convert it into an img file and using mapsettoolkit export it to mapsource - not straightforward

I’ve tried to automate the process as much as possible by creating a GUI at http://www.pinns.co.uk/osm/mapsourceuploader.html