Just had a thought that whilst not obvious, the police role equipment should contain some useful information, the camera/skyforce nav systems will have times of power on and off. Camera heading/attitude/altitude measured against against aircraft position etc The power off should have happened when the first engine ran down and took the generator off line, this might provide the time frame between first engine flame out and time of impact as I understand the engine FADEC only records the engine run time rather than actual start and stop times (might be wrong on that).
A long shot but I'm sure the AAIB are having it all checked. I also wonder wether there was any call from the TFOs to control, for 2 minutes to land, or informing of any fault that might preclude further tasking that night due to faults on the aircraft. certainly something that would be fairly standard for my crew to do if a fault occurred in flight. It just all smacks of things happening really so quickly as to overpower normal procedure and responses.