With the airline (BA), Manufacturer (Boeing) and the British AAIB-CAA etc etc involved, as well as other agencies...
Being blunt and upfront literally, -- NO offence intended to any member of the crew -- no one seems to be any further forward after almost 7 months of extreme head-bashing, early mornings - long afternoons and late nights around computer simulations, test rigs, theory upon theory etc etc etc...
No one seems to agree on any particular 'reason' for this happening. Leading on from this, when do the authorities decide to call it a day - if at all?
Is this another 'unknown' phenomenon... In which case, basically case closed...