Originally Posted by
PETER01
Hi
jsh4ft and welcome to the BA Board here.
I've never flown on the A350 and in the absence of any replies meantime it looks like it's a standard width to me at just a tad over 17 inches. From the photo in post 2 (by
teledude 
) as below, the seat middle armrests are all fixed with the TV monitors folding away Into those fixed armrests.
Thank you. This is not good for us - solid armrests on both sides of all three seats - I will have to try and change, likely at the gate.