Fwiw a mate switched to Sonos in their 1 bed flat and it still works well in that space. Their kitchen is separate and I think they have another in the bedroom.
They still have a nice separates set up, but it basically gets no use due to the volume x space x ease of use.
Thanks all, I think some kind of Sonos set up is the right way for us, we have a pretty low tolerance for bad UX and I need this to be fit and forget.
Will probably start with a single Sonos One then add a partner down the line.