Yes they’re 9 across. Seats typically narrower than older planes. Although 777 being refurbed from 9 across to 10 across so going the same way. Reports that in window seat the curve of the fuselage impacts shoulder room, and aisle is narrow and passing trolley and foot traffic results in bumps and disturbance.

In fairness this problem is not unique to BA. Is WT+ in your price range?

On a positive note the B787 and A350 really do have improved air quality that helps hugely with overcoming flight grogginess and jet-lag.

Maybe of help 35J25W154Y The BA Source