Jim: I've now listened to Feedback. They didn't say anything useful but promised to get someone on the programme to explain. Please let us know when they do; I'm not prepared to sit though the programme on spec.

https://www.bbc.co.uk/programmes/b006slnx/episodes/player

I expect that Sounds (which used to be called Radio iPlayer) will become geographically limited by IP address as the TV iPlayer always has been. The lady in North Carolina who listens to Radio 2 and the guy in Kansas who listens to Radio 6 will have to use a VPN. Nodody in the BBC is going to tell them that, though. Perhaps the BBC will come up with a subscription service.

I expect that the BBC's direct audio streams, used by other streaming boxes and clients, will also be IP-limited - apart from (some) Radio 4 and World Service.