Enjoy taking your M3W to France - great roads and as noted above, a bit of research will identify hotels with off-road parking - we have done many such trips in ours. One other suggestion extending Stevo666's ideas is to take the ferry from Portsmouth to Santander and drive back via Bordeaux to the ferries from St Malo or Caen - we did this back in 2012 with our brand new M3W - even near continuous rain did not stop us enjoying the trip.
If you have not done them already, just make sure your M3W has all the recommended updates for long haul touring (fuel pump etc - see buying guide). With these done, they are pretty reliable as witnessed by the 13 of us who did 3000km in Morocco back in Feb with minimal trouble ... and if the worst happens, Steve @ M3WServices will certainy sort you out!
