Yeehaw22
"If the aircraft was being prepped for dep, then there's every chance the messages reappear on power up or even power changeover from gpu to apu. The 787 is renowned for this. Hence why they need clearing before departure and not on arrival."
Except that the AAIB report makes it clear the snag was already in the Tech Log as an ADD from a previous sector. If it wasn't considered acceptable to dispatch the aircraft from LHR carrying the ADD (which is understandable), then WTF had BA been doing since the aircraft's arrival a day-and-a-half previously ?