In reply to andrew breckill:
A return by car from Birmingham tends to be about £500 - fuel, tolls, Channel crossing and normally a cheap hotel on the way out. A bit less if you get a really cheap Channel crossing and sleep in the car.
Of course it's not just about the cost, it's also the convenience of getting around once there, particularly if you don't want to be in the Cham valley all the time. It's easy enough to get the train / postal bus to Switzerland but it's not cheap (I think Zermatt to Cham single by train was about €80 earlier this year).
I guess public transport is environmentally friendlier as well.