I did a lot of voluntary work at the museum between 72 - 75, including the major refurbishment of the Spit V and Heinkel 162. Anyone remember Cpl Bertie Coombes, Chief Tech Jeff Richardson and Sgt Wally Hooper?
Regarding buried bits, I was employed as an MoD guard for a while in 1977 while contractors were carrying out conversion work prior to the Army taking over. Opposite the NAAFI shop and just to the right of the Post Office, there was a fairly large grass area buffering the AMQ (I forget the name but Poplar Way does ring a bell as being adjacent). A JCB was digging a trench and unearthed a corroded main landing gear which looked to belong to a Curtiss P40, judging by the bevel gear at the top of the leg. There was no evidence of crash damage as the assembly had clearly been unbolted from the wing structure. So, there might well be more parts buried in that area.
I don't recall a Hastings being on the fire dump but there was the forward fuselage of a Shack. I witnessed the tragic XV198 accident in '73 and still have the Air Clues magazine relating to it.