Nutloose -re contracts, I stupidly forgot that by 1992 at the latest there was a database in the MoD(PE) DG Defence Contracts which held sample development, production, spares and repair contracts for each of the hundreds of contractors. (As I said, PDS contracts were done separately by TAs, basically because the work was 100% airworthiness related). The Executive Officer (Ray S) who developed it will hopefully forgive me. Clever bloke. His DG (2 Star) at the time was a jock who used to put the fear of God into wayward contractors.
Engines - I think your analysis correct. Bits and pieces have emerged. I wonder if AVM Turner's admission there is no safety case is the least of it? And similar to your JSP400 example, Ministerial briefings have to include a risk assessment discussing the possibility of the correspondent revealing all to the media or in print. It's amazing how often they say "no chance" and get Ministers to lie.