FWIW - I've got a booking in AUG2015 on the 744. I'm in 64K on both legs of my booking. My seats have not changed. However, I've just logged into MMB, and surely, 64A is now occupied on both seat maps for both flights. As of yesterday however, I was the only occupied seat on the UD for both legs! BA must have changed something overnight re: blockage of 64A.