In Praise of Frank...
I have given enthusiastic feedback on Sonos Telephone Support before. Forgive me for doing so again, but the help I got from Frank yesterday reaffirmed my admiration for Sonos.
I won't bore you with what was wrong with my Sonos installation, save to say that it was a complex combination of network problems that was effectively rendering the system unusable. With commendable patience, Frank cheerfully spent almost an hour on the phone carefully diagnosing each one, solving it and testing it, before going on to the next problem. Note, much of this time was taken up with me pounding all over the house power-cycling ZPs, while Frank uncomplainingly held the line.
I am hugely grateful, and would reiterate to all those having problems with drop-outs or other poor performance: give the folks at Sonos Support a call - they are excellent.