Q: how do i buy music from the uk?

What country are you in ? Unless you are here in the UK with a UK billing address on your account then you can't buy content from the UK store. If there is an album that you'd like to buy which isn't currently available in your country's store then you can try requesting that it be added, but unless the rights-holder for that album for your country agrees to it then Apple won't be able to sell it there : http://www.apple.com/feedback/itunes.html