With regards the route from the UK, I've taken onboard the advice to go France -> Belgium -> Germany -> Austria (rather than France -> Switzerland) and have booked into a nice looking motel at Kempten, Germany (not far from the Austrian border) for our overnight stop.
One further question on this though.....
Are the traffic problems going via Switzerland as bad going back as they are coming down? Or is it worse in a particular direction?
I'm thinking it would be nice to come back via the Swiss alps rather than go back the same route we came down by - a change of scenary and all that. But if it's as bad going north across Switzerland as it is going south then I may re-think that one.
cheers!