With reference to the Dunsfold Harrier, if I recall it was concluded that because the a/c was climbing out to the west, the pilot would have had the full glare of the sun in his eyes, and it was said that he would have motored his seat downwards to be in the shadow afforded by the instrument panel until he levelled out/altered course.
Again, if memory serves me correctly, it was possible somehow to take the seat down too low, resulting in some kind of obstruction snagging a cable on the lower part of the seat, the cable's function being to release the drogue. This apparently happened and extracted the pilot.