In reply to Em66:
Sportscover Direct will do it. I'm not endorsing them as, though I use them habitually for climbing trips outside Europe, I've happily never had to claim so no idea how they behave in such circumstances. Booking procedure and telephone advice all very good though. Give the right impression and definitely meet your needs - cover only activities (not baggage, cancellations etc etc) and only on the days you're exposed to risk.