Thank you for the clarifications and information. I was a little unsure if there was a way to connect everything to my main system using a single amp or other box and then distribute to other rooms.

It seems that a Sonos Connect:Amp (ZP120) will be my best starting point for he bathroom. I really love the play history and information hat builds up with Sooloos, which Sonos does not appear to have, plus didn't really want 2 different libraries of information. I'm aware that my tracks ripped for Sooloos won't directly work on Sonos, but am assuming that there's a way I can convert them without having to physically rip from the CDs again. Playing via an output on Sooloos and into Sonos does also sound like an interesting option worth exploring.

Trinnov Altitude 32-8-16, Meridian 271, Front: DSP7200SE, Centre: DSP7200SEHC, Rear: DSP3200, Ceiling Front & Rear: DSP320.2, Sub: Velodyne DD15+, MC200, Oppo 203, Sony VPL-VW360es, Lumagen 5348.