I used to fly Gatwick - Belfast with FlyBe pretty regularly several years back, and it was always a bit tight in the 3+3 config. I'm also 6'4 with wide shoulders, and more often than not we'd spend excessive amounts of time on the ground at LGW waiting for a slot.

The BA ones are exactly the same, and in my opinion they are nothing to worry about. A noticeable difference, yes, but enough to impact on the overall flying experience? Not at all.