Radio 4 voice command stopped working

I get the same issue.  If I disconnect the Sonos speaker then Google works as it should - in this case plays BBC Radio 4. When I re-connect the Sonos speaker it will on play BBC Radio 4 Extra

I have the same problem too. 
 

On the plus side I had BBC radio support from google assistant to Sonos missing for several months last year and it did get resolved in the end. 

Hello All!

Just to update you on steps I took since I posted.

I wrote to Sonos, TuneIn radio and BBC Sounds. 

I’ve been in lively email exchange with the first two. 

Because Google Assistant on Sonos uses Tune in radio to play BBC radio stations I went to Tune In Radio to see if there is some kind of mix up on their streaming links database… I’ve responded to numerous questions and sent videos to demonstrate the issue and today they said they’ll send it all to their technical team to look into. 

Sonos also took some time to accept that there is an issue and said that they will forward my report to TuneIn. However, the issue w BBC World Service not playing is I think a problem at the Sonos end because Google Assistant on Sonos sometimes (but not always) tries to play BBC World Service via something called VPR. So I have asked them to look into that. 

No word from the BBC. 

If I get anything useful out of this email exchange, will update here. 

Wow! Perseverance. Well done.  Great to know someone is continuing to press on this.

Looking forward to your updates.

@James L. et al

So, over a month since this was reported and acknowledged…

Must be a tricky one.

I am pretty certain now this is due to Sonos defaulting to using TuneIn to stream BBC programmes. It is TuneIn that wrongly points at BBC 4 Extra, not Sonos or Google Assistant. 
When auto connection between GA and Sonos system gets decoupled, GA resorts to BBC Player and then plays correctly everything. When attempting to play BBC 4 through TuneIn, problems begin. 
This is my umpteenth issue with TuneIn, and the reason why I have removed it literally from all the gadgets I have. But when Sonos, lazily, goes to them, they needlessly introduce problems into an otherwise good system.

So frustrating - same issue here, exactly as described. Watching this thread to see if/when anyone gets more info. Thanks everyone for exploring on our behalf.

Just trying out a new Sonos one. Radio 4 is my most listened to station so this bug is frustrating. Seems like a simple issue with GA and TuneIn integration. I’ll try contact Sonos today.

This is typical of Sonos poor UK consumer support and lack of an effective complaints system. I won't buy more Sonos because of this.

This is getting a bit ridiculous now - how can there always be so many issues with voice activating radio stations. Genuinely no idea why Sonos moved into the smart speaker segment without the support team to make sure the service works? I’ve had a one since it was launched and this issue has to be at least the 5th time activating radio 4 has become impossible for a long period of time.

Sort it out Sonos, people will lose patience if you can’t do the simple things right.