Chug
"When did this change to the RAF Flight Safety system occur, did it only prevent engineering based IRs being submitted, or all? Who was supposed to stock pile these IRs before bouncing up 'omnibus editions' to higher echelon".
Not just RAF, but MoD as a whole. In fact, the RAF didn't suffer as much as the RN, as the former held the funds.
The decision not to release funding for fault investigations was entirely made by supply managers, in the years following their rise to power in the 90s.
Engineering Authorities were "discouraged" from raising 760As (Fault Investigation Requests) following receipt of Narrative Fault Reports. The direction was that, an investigation cost £xx, invariably the MoD were held liable and so had to pay for rectification (for good reasons - another issue), so there was no mileage in conducting investigations in the first place.
Non-technical staffs were routinely making engineering / safety / airworthiness related decisions. You can see the obvious conflict with Airworthiness Regulations. This Suppliers' policy was enforced by their 2* ordering disciplinary action against those who complained. (My annual reports are quite entertaining, in a masochistic way). A simple matter of record, which is why I feel comfortable discussing it. If MoD don't like me repeating it, they should be more careful when trying to justify their actions in response to FoI and DPA requests.