JB - I've not commented upon any criminality taking place, I've merely commented upon what one might see in such a situation.
I think this discussion is taking place (forgive my assumption) because of this:-
Shoreham crash: Police go to High Court to see evidence - BBC News
Where it says "Det Ch Insp Paul Rymarz said aviation law blocks access to some Air Accidents Investigation Branch (AAIB) material.This includes cockpit recordings and footage, witness accounts and specialist reports"
It is my personal view that filming with a Go-Pro is not done for flight safety and so the various arguments that relate to other recorded aircraft safety media do not apply.
My reference to Mr190 mph is that you initially suggested recorded media of a 'Go-Pro' nature were "inadmissible' and that suggests where such material shows laws have been broken video recordings are admissible as evidence.
I do not understand why the police should want to see any footage of any primary flight instruments. Whatever the instruments display, no criminal offence took place.
In which case that information could be volunteered freely and would, for example, clarify what readings were on the altimeter that of course the pilot was using to reference his height...