I wouldn't trust any branch of the Services to know where to find such things. My father was Captain of HMS Hardy and the first UK vessel on scene when the Aer Lingus Viscount crashed in the St George's Channel in the 1960s.
For years afterwards the conspiracy theorists were saying it was brought down by a missile from Aberporth. The MoD went to look for the ship's log for a much later enquiry, and could not find it. My father had a visit over thirty years later asking what he had.
