I say do it - I have no idea whether it would help your aviation career, but if you've got the opportunity it sounds like a load of fun!
You are quite right that you could continue to learn to fly in the UK - there are plenty of schools, both powered and gliding. I don't see how being in the Alps would give you any advantage in an aviation career. In fact, I would suggest that a variety of different flying environments would benefit you. I've done a bit of mountain flying when I did my hour-building in Arizona. Most of my flying has been in the UK, but I've also been to the Channel Islands, France and Belgium. I've also done a bit of aerobatics, got a sea-plane rating and a couple of hundred hours of tail-dragger flying. I've learnt something from every single one of these experiences, and I hope they make me a better pilot. I don't expect them to necessarily swing a job application one way or the other, but that's not the point. And, most important of all - I've enjoyed each new experience, because that really is the only reason we get into the flying business to start with.
FFF
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