Have you checked that your location is set properly on your account at www.sonos.com? I believe Sonos forwards that data to BBC, since the BBC is frequently geo-restricted, at least on certain streams. 

Sorted now, had to remove and reinstall bbc sounds app

Well BBC Radio 4 and all the other stations no longer list in SONOS or in TUNEIN. 

As of this morning (8 am EDT)  I have R4 set as an alarm and it worked yesterday and today not. 

BBC Sounds does not show up in services. 

NONE of the BBC stations show in SONOS Radio or in TUNEIN 

In the TUNEIN app on my iPhone to which I have a paid subscription 

BBC Radio 4 now shows the following message. 

    Regional Restrictions
    This station is not available in your region. 

Honestly this is so upsetting … 

BBC itself said that BBC RADIO 4 and WORLD SERVICE would be available TO ALL ANYWHERE. 

And now they are taking it away ???

That is the article where they said that 

https://www.bbc.com/news/articles/c8j1m721mp2o
“The BBC has said its radio stations will continue to be available for people outside the UK to listen to live after BBC Sounds access is restricted for international listeners.
The BBC said listening to BBC audio programming on non-BBC platforms would not be affected by the change.”

There is nothing on the bbc.com website about this. 

So as of today nothing from the BBC anywhere in the world. 

This is a sad sad day.  I am utterly gutted

It used to be that you could install BBC Sounds if you temporarily changed your country to the UK. Not sure this still works.

Strange thing is that as of two days ago, I can’t play BBC radio stations on my Sonos speakers…

But I can still play the stations on my Bluesound streamers. Does that mean it’s an issue with Sonos rather than BBC?

Unlikely. The stream doesn’t exits ‘on Sonos’ until it reaches your network. Many/most companies maintain their own servers with the Sonos MAPI on them to serve Sonos streams. So, either the issue is at a streamer (such as TuneIn, although they also tend to point to a stream provided to them) or the origination point.

Just as a guess, based on what I’ve read here, BBC may have made a change due to geo-restrictions, and hasn’t got it ‘right’ yet.

Well the great news is - it started working again this morning.

So I don’t think it was due to something that the BBC did. I am using the Sonos Radio service rather than TuneIn, and didn’t have any problems on my Bluesound equipment. So I think it must have been a temporary bug somewhere between BbC and Sonos