In reply to Blunt: I got my insurance for 6 months in Australia for here:
http://www.charterflights.co.uk/travel-insurance/
It was about half the price of BMC cover at the time.
They include an option for "climbing (up to 4000 metres)", I phoned up to ask a question and the lady who answered assured me that the 4000 metres is not an absolute altitude limit, rather, whatever height you start your climb, you can climb continuously for 4000 metres before the insurance is invalid.... I wouldn't like to test that theory (mainly because I'm sure she was wrong) but as a coverall for everything from soloing to winter alpinism, it's cheap at the price.
(An btw, if you are bouldering at font just get normal insurance. Even if you smash yourself up, it's not like you are on some sort of multipitch route. Make sure there are no bouldering mats present, take off your climbing shoes and tell the paramedics you were just having an exploratory walk near these cool boulders and fell off when you overbalanced, should be covered by pretty much any holiday insurance.)