I rode in the alps on my heckler a few years ago and it was ok, rode it last year on my bullit and was better, hopefully going out this year with a 224 and think that will be the right bike. However we only tend to do the DH runs hence the DH bike! Plus I ride my DH in the UK too so its not like its going to waste.
I like the idea of getting a (cheap 2nd hand) bigger bike to go out there as it means you don’t have to mess with your UK trail bike as stuff can easily get broken in and enroute to the alps! More suspension and bigger brakes made the 2nd trip far more enjoyable for me as my hands and arms took a bit less of a beating. As a result I could rider faster for longer compared to when I was on my trail bike.
Who knows if you get a DH bike you may well use it a fair bit in the UK too!