I too found some pieces at Syerston with part numbers stamped. Interestingly my brother-in-law got the haulage contract to transport the myriad of 'spares' from Waddington to Bruntingthorpe when 558 was sent there. Amongst the smaller pieces was a burlap sack containing a several rather badly disrupted aircraft parts. Each one had a F731 attached, red side outermost, identifying them as part of VX770 and categorised as CAT5(S)!