Upvote:3
Adrien posted the link in a comment to another answer on multiple types of insurance. I had a look at one of them (truetraveller) which does British quotes - it asks 'where do you USUALLY live', and it appears possible to buy from overseas.
I plugged in a sample 1 month policy for worldwide excl USA, and it seems cheaper than what you're finding for yours, but as always I'd expect you to investigate the details clearly and make sure it's applicable to your and your situation. No coming back and blaming me! :) (This is why I'm not mentioning exact prices or conditions). However, it seems like a much more reasonable option.