Just a bit of advice for anyone who might do this.
1. Hire a car on the Swiss side not the French sector
the main advantage is you get the pass for the Swiss motorways
we had to navigate through Geneva city centre using the sun until we eventually found a sign for the Mont blanc tunnel. Like wise coming back we decided to avoid Switzerland all together , this adds 30min to the journey.
Wee bit scooter related - Geneva is a scooter and bike paradise, saw hundreds of them.
My trip was from Geneva to Cervinia, only saw one scoot the whole time we were in Italy.[/img]