Thanks Everett, I'll look into the Denon system.
The plan is for 4 rooms, 2 speakers in each:
Living room (where the receiver would live)
Spare bedroom/studio
Bathroom
Kitchen
I've looked into some multi-room systems (e.g.
Russound’s CA4) but the price (£1000+) is too high, considering there's then the addition of the amp, speakers and cabling
I'm now thinking I might need to give up the individual room zone idea and just have a signal source broadcast across all speakers. Using the Onkyo receiver's zone 2 output I could then use a splitter (
example) to select all/some speakers, reserving zone 1 for the living room TV. That's presuming the receiver can output two independent sources at once...