Hebog --
Thank You for the altimeter responses. So we will like the AAIB presume AH did follow procedure and reset the altimeter and do all the necessary fiddly bits which I take would allow for the different altitude at Shoreham than North Weald.
The pilot had "retrograde amnesia" which is common after trauma. I had it after a car crash in 1976 and I only have one very short recollection of the events from a couple of hours before. I suspect that even my one recollection might be inaccurate. Our brains fill in gaps with - frankly - fiction. It isn't a lie, i.e. it isn't an attempt to deceive, it's just the way our brains work after trauma. If you're interested you could google for "confabulation" which will take you to some learned papers etc.
As for the "fiddly bits" I think we can safely assume the pilot did these and would have done them in his sleep. Unless he was seriously mentally incapacitated for some reason in which case if he was feeling out of sorts why didn't he divert?
Few pilots have a death wish.