In reply to Mike Conlon:
Do the mini bus from the UK option because if the weather is not good then you can go somewhere else with the mini bus. So many people book flights, accommodation etc only to land and the weather shut down the whole trip. Then people spend the trip walking around gear shops looking up at the cloudy peaks.
If you have the flexibility of driving from the UK you can just go to another region of the Alps at last minute or go sports climbing instead, on the way down. Read up alot about places to go eg. Chamonix, Ecrins, Pyrnees etc. Also read up on classic sports climbing areas eg Verdon, Boux etc.