Nortonbeak,
G-YMMM is an insurance write-off and will never fly again. It is possible that parts from the wreck have been sold to BA by the insurer who now owns the aircraft.
If the decode was correct, then either the box from G-YMMM is in another aircraft, or somebody has wrongly coded the box in the aircraft you picked up.
The AAIB investigation into the crash landing continues, with fuel starvation being the most likely cause. However, as there was plenty of fuel in the tanks, the on-board computers worked as advertised and there is no suggestion of flight crew error - the cause of the incident has yet to be determined.
See the AAIB reports so far here:
http://www.aaib.dft.gov.uk/publications/special_bulletins.cfm
