Incidentally the longer wing and active aileron mod wasn't ready in time for the first deliveries of the BA -500 and several were returned to Lockheed for the wing extension work. When the first one came back it soon got damaged when the tuggie followed the wrong white on the hangar floor, the -500 one was offset by a foot or so from the normal line but he forgot what version he was towing, result a crunched wingtip.
After they went to the RAF one had a very heavy landing at Brize and a big enough bounce that a go around and circuit was required during which a large amount of fuel was lost through diagonal crack in the rear spar, the BA crash team carried out the subsequent repair that took months to do. Does anyone know anymore about this as I believe that it nearly wrote the aircraft off.