Row 16 Club World (and to some extent row 15 and 17)
I just want to put some comments on the window seats in row 16 for night-time, flat bed, services. I recently went on the Dubai to London Heathrow service, which is 7 hours long, and my report is here:
https://www.flyertalk.com/forum/31484824-post809.html
Now I have no hesitation recommending the rear cabin in Club World for day flights. It is much smaller, quieter, with good access to the toilets, usual exit door, Club Kitchen. However I did notice that in flat bed mode, the seat seemed fairly noisy and prone to a strong vibration effect from the engines nearby. Rows 15 and 17 were the same (I had the cabin pretty much to myself for the whole flight, though there were 4 of us down for the cabin, 2 passengers asked to go forward for unrelated reasons).
What I think the problem is that when in flat bed mode, the seat frame and chassis are on a similar plane to the fuselage's dispersal of engine vibrations, so it's just too close. When I briefly tested row 9 this effect wasn't anything like as noticeable, and was less noticeable in 15E.
More reports would be useful, inevitably this is just from one aircraft, WBA, since though I've now flown BA's A350 five times, it's all been on the same aircraft. It may be just a feature of this machine.
By contrast, a few days later, with memories still fresh, I was in row 3 of Finnair's A350-900 to HKG, and this was far quieter, but obviously I was a lot further away from the engines here. Incidentally BA's product is vastly better than Finnair's equivalent, and indeed Cathay. I was never a fan of their A350 seats but not the gap is enormous and I will positively try to avoid CX and AY on A350s now. I actually prefer AY's older A330 fleet, at least they have air vents, and seating similar to the BA321 midhaul aircraft.