FWIW, I was treated to 56D on a LHR-JNB last week. (It almost seems as if BA doesn't want me ever to try the WT+ cabin on a 380, even when I've paid for it. )

It's a good seat if you like the soothing sounds of galley stowage doors and trolleys, and the gentle percussion of tea/coffee pots, particularly in the early morning. However, I now have to add this to the list of seats that I wouldn't voluntarily pick for noise reasons.

It was also interesting to see that 50B was unoccupied (I didn't notice whether or not 50J was), but one benefit was that I nicked its pillow for a more comfortable night's sleep, and both the bed and the sleep were very welcome and much appreciated.