The GPX export you have is really good as it seems to make an exceppent compromise between having too many points (my device would be constantly beeping, and it has a limit of 250 points per route) and not enough (so it wouldn't capture the turns in the route properly).
However, to use the GPX file for navigation on my Garmin GPS60, I need the route to be a GPX "Route" rather than a sequence of track-points. I can do the conversion from the file I export from cycle.travel using GPSBabel, but it would be more convenient if you also offered a direct GPX Route export. I think it would also be more logical to provide the data in this format, as it's a route that's being described.
So would it be possible for you to add a "GPX Route" export option, in addition to the current "GPX Track" one?