Ah, you didn't see my follow up post!

"Well, I shouldn't go by memory.
I've been able to reach a new shoot, so this may be young leaves rather than mature. It's still too wet to go climbing.

The leaves are in clusters of about 6. Each leaf is simple, about 2cm x 1cm, broad lanceolate, serrated, rather thick, glossy green. Not in the least bit like alpina!"

Sorry about that!

From what I could see of the flowers, the petals seemed to be slightly rounded at the tips, whereas all the alpinas I've seen have had quite pointed petals. So with that and the leaves, and that fact it was flowering a good month before my other alpinas (the first of which has only just come into flower) I'm pretty sure it's not an alpina.