Hi Guys, thanks for your help.
When I got everything set up to some degree though I kept getting buffering problems. Then I saw somewhere that a Sonos Boost would normally solve that issue. So I bought one.
Had a lot of trouble setting that up but then got on the phone to a nice guy at Sonos (on the phone for about an hour) who helped me set it all up. I set a trial track going and made sure it went on for at least 2 minutes (3 in fact, which was more than the buffer had ever allowed before) and then said goodbye and thank you. It was after hours at Sonos by the time we finished so I wanted to make sure it was working because I knew I wouldn't be able to get hold of him until tomorrow again. So I rang off and enjoyed the music for a bit longer - and then it stopped again, once more with a buffer message.
Is there any more help you can offer? I have a functioning Sonos system, it is talking to the B2, it is apparently running with the aid of the Boost (the guy did diagnostics to see that it was working as he expected), but it still stalls after a few minutes and says that there is insufficient buffer to cope with the playback.
As you say, when it works they seem to be a great team, but I'm obviously not there yet!
Many thanks
Don