Is BBC Sounds supported in all geographic regions? You should check it’s available to you. 

https://www.bbc.co.uk/sounds/help/questions/listening-on-a-smart-speaker/sonos

Thanks for the reply. I am in the UK and use the BBC sounds app on my phone so I would have thought that would be ok.

Does anyone know how to check what country your Sonos account is registered to? Mine should be the UK but I guess I should check. 

Go to www.sonos.com, and log in to your account, then check your settings for your address. 

Whilst you are at sonos.com checking address, even if its correct, I would change it slightly (eg capitalise a letter), save, then change to be your exact address and save again. IIRC, this forces the Sonos back end systems to refresh your address, but only if its been edited and re-saved.

Thanks everyone. The address on my account in Sonos.com was empty and the country had defaulted to the USA. All fixed now.