In reply to Tallie:
No, I don't think there's any nowadays, although I might be out of date. Have you trawled through the provider list on the ELCAS website?
Plas y Brenin (and I think GL too) used to be registered to deliver a smattering of MT courses but there was so much bureaucracy/admin forced on them by ELCAS that it just wasn't worth their while.
The closest you might get is Nonstop Adventure who do ski/snowboard instructor courses that are on the scheme. You could approach a provider to see if they're willing to jump through the hoops with ELCAS to get registered and get a MT course approved but it's a whole bunch of work for them. The difficulty of hoop-jumping also depends on whether the MT course already maps across to UK's Qualification Framework (eg. I believe that Summer ML still does (at Level 3, equiv to A Level) but MIA/MCI never has, which is why ELCAS has never deemed it worthy of being funded).