James,
As someone who had an engine failure just after take off from Oakington (in a Varsity), I can certainly attest to the fact that the ridge behind Dry Drayton rapidly becomes a significant obstruction - or more precisely it was a tree on the ridge line that filled the windscreen for some time. However, that was take off, and when landing, even assymetric, we would be nowhere near the hill.
One thing you haven't mentioned - which may be quite significant - is whether the wreckage was spread out in a more or less straight line, indicating a 'relatively' controlled flight into the ground, which could come from a mis-set altimeter, or essentially all in one place, which is more likely to be 'uncontrolled' as in a spin in from low level as a result of previously unknown battle damage or pure disorientation on a low light night. We tend to forget just how dark it could be with a blackout in force and just a few runway lights (as well as possibly Bourne, Waterbeach, Mepal, Warboys et al all around). Flying and manouevring at low level over the sea at night with just a few ships lights around soon brings that home. Even recently I have had students flying circuits on 'good' nights get disorientated and just increase the angle of bank into a spiral dive through lack of attention to the instruments when turning finals and they were well rested and not returning from operations!