Within Route Converter, I saved the file as a Magellan Explorist (*.trk) file.
Now comes the disclaimer....
Since posting the original URL, I have found problems importing some .gpx files into RouterConverter - a track seems to import fine, but a trail doesn't
I have since found another piece of software that read in a trail and exported a new gpx file that was compatible. http://benitools.info/itnconv.zip
It is not as good as RouteConverter but may help.
Don't think I have finished the quest for the ultimate route conversion software, so am going to continue looking.
If found, please return to the pub.