Trouble playing the radio on a group of Google Home speakers

Murmansk

I use 4 Google Home speakers in different rooms to listen to Radio 4. I have the speakers linked via the app in a group called Home.
I was used to saying "OK Google, play BBC Radio 4 on Home group" and it'd play out of all speakers and they'd all be in sync. Great, and cheaper than a set of Sonos speakers.
Over the last few months it's been getting very frustrating where I'd say the line above and then - nothing. About 70% of the time it wasn't working.
I rebooted all the speakers in the hope of them updating their software and that just resulted in a more or less 100% failure to work.
Well I've just discovered that if I say "OK Google CAST BBC Radio 4 on home" it works as it should so my frustration has been eased for now and I hope someone else may find this tip of use.

RumRat

You can also use "Stream Radio 4 on home" you shouldn't need to use 'BBC'
I have a similar set up, but, 'Play' still works and I listen to Radio 6 Music. 
If you ask it to 'Play' on individual speakers does it still work? You could also delete your home group and set it up again, that may bring it back around to it's senses.

Murmansk

Thanks I'm pleased to find "Stream radio 4 on home" does indeed work and yes, I can ask it to "Play" on individual speakers. I'd previously tried deleting and recreating the home group but it made no difference.