Originally Posted by peter h

Before it goes into service, it's probably too early to speculate! However, as my only experience of the A350 family to date was on a CX A359, I've had a quick look at their A350-1000 layout on SeatGuru:

BA 56J, 56W, 219Y - total 331. CX 46J, 32W, 256Y - total 334
Toilets: BA 9, CX 10 (an extra one at door 1)
'Full' galleys: BA 2, CX 3 (an extra one at door 2)

There's obviously some space advantage for CX having more a lot more Y seats which would make the extra galley easier to fit in. Interestingly, they have their 6 Y toilets around door 3, whereas BA seem to have 4 at door 3 and 2 at door 4 (where the rear galley is).