Perhaps BBC Radio has a large music footprint? I know the BBC is public in a different sense from USA Public Radio, but hopefully has good stuff. A lot of the NPR stations are college radio as well. Do Universities in the UK have their own stations? If so, perhaps they stream too.
The WGLT public station in Bloomington, Illinois streams worldwide. I imagine many of the other stations on the NPR list do too. All you need is the internet.