BA's systems may show you other of the seats currently with an X as more passengers check in, so keep it flexible by not printing the BP and something more favourable may pop up hour by hour. But it does look very busy so deciding if you want to scrunch into a window seat, sprawl semi-aisle while being tripped over or go middle-of-middle where no-one will need to climb over you may be the best your options get. WTP and forward cabins also looking busy, so unlikely that you'd be able to get an airport upgrade into more space for a few hundred dollars (as opposed to seat fee in Y).