According to BBC radio stream page: "The way we stream radio is changing so we'll no longer be providing Windows Media Audio streams. Here's all you need to know about the change. ... / ... We have now (Feb 2015) started switching off Windows Media Audio for on-demand and Live radios streams will follow soon after .../... For live radio, each station will now be broadcast in the SHOUTcast mp3 format. This should work for most devices."
Then, since the beginning of februar 2015, *.asx streams of BBC radios (like asx stream of Radio1 for example) can not be played anymore with Rhythmbox. Playing this BBC radios axs streams, gives a voice explaining that this format is not supported any more.
Then, how could BBC music live radios (Radio1, Radio2, Radio6, ...) be now listened accross Rhythmbox ? Which stream format ? Which urls ?
get_iplayer
comes to mind, which I think can stream as well as download. You probably shouldn't use it if you like the BBC rules (BBC's Online Managing Editor's stance on 3rd Party stuff here - this was cited as a reason the original dev of get_iplayer dropping support)