Thanks again for all the replies, especially the offer of a personal home demonstration! Really appreciated!

I am still slightly put off by the fact you need the Sonos app, and that they don't have Bluetooth which seems ubiquitous... apparently you can't play YouTube video audio through the Sonos speakers!! I do this quite a lot with my Soundlink. Sonos therefore seem quite restricted... having said that, they seem super popular and are doing well so they must be ok in reality...

Anyway, thanks again!