One of my first crushes (June Allyson, not Jimmy Stewart!)..."honestly!"
Lots of theories, but basically the Norseman (which is not much better than a light aircraft), took off in cr@ppy weather, to fly through cr@ppy weather over the channel in wartime with, of course, fairly basic instruments. Recipe for disaster. I am not blaming the pilot per se, but he could easily have become disorientated in cr@appy weather....however, the conspiracy theorists will have you think otherwise!