" a very immature variant entered service too quickly"
The entire aviation description of the Mk7
"The best bit of procurement in recent military history"
The two are not mutually exclusive. If you look at the RTS at date of accident, crucial parts of it reflect the AEW Mk2 circa 1996. As did the interoperability procedures with CVSs, the necessary contract to reconcile them having been cancelled by non-technical staff. The RTS was a cut and paste job without checking validity of, especially, read across. Hence the problem whereby speech intelligibility and the comms system in general was seriously compromised. (i.e. What you characterised as having "no effect on their situational awareness" which, coming from a pilot, I suppose I must concede. Just glad I don't have to implement any spec you have written!). In the same way the Chinook Mk2 RTS didn't come remotely close to reflecting a Chinook Mk2 in June 1994.
"Maturity" has a formal definition in MoD, measured (at the time) in technology and system integration readiness levels. ASaC was close, but short cuts had been ordered in critical Safety Case areas by the same non-technical staffs; for example, structural and electrical integrity. The Critical Design Review for the whole aircraft was waived by a non-engineer, which of course would have flagged the contributory factors noted by the BoI (yet again, because they'd been flagged in 1994-97). Similarly, system integration was largely waived. This crucial work was conducted in the background by Westland (a sub-sub-contractor, but actually leading player) and the programme manager, and hidden from the non-engineers and beancounters. That is what resulted in the "best bit of procurement in recent military history"; not the formal contracts and behaviour of ASE, DHSA, the IPT and parts of MoD(PE). Therefore, in a way I disagree with it being the "best bit of procurement", because it was actually the willingness of a small team of 2 (!) to serially disobey orders that made it SEEM a success. But you wouldn't want all programmes to be run like this, if only because there are so few willing to risk their careers, and even fewer who would know how!
As the aircraft had not been "Proven to work in its final form and under expected conditions", by (Secy of State and Chief Scientific Advisers') definition it was still a prototype. I'd slightly modify that statement if 849 had conducted trials on the way to the Gulf and the results had been fed back and plugged into the ongoing conversion programme, and ADS retrospectively amended - but I know the latter was not. One of the unproven parts (because the
RN had stated there was no requirement at all for HISL and hence trials had not been scheduled) was using HISL or the new avionics off a ship, at night. When non-technical staff agreed HISL could be fitted to the 2nd Mk7 trials aircraft, no trials took place. (MoD claims it was in the first aircraft, but the pictures don't lie). Thus the first HISL trial was conducted by the BoI, who confirmed the
installation (not HISL itself) did not meet the laid down design and airworthiness criteria. (With respect, this is where you don't recognise the difference between HISL and the HISL installation. No one has ever said HISL was not airworthy; it was the installation, which is much more than the strobe, combined with concept of use and lack of other defences in depth). The BoI were not told others had concluded the same some years before, so presented it as a revelation.
Unverified read-across was granted from HAS Mk6 (not AEW Mk2) to Mk7. Forgive me as a mere civilian, but the HAS Mk6 is quite different, and operated quite differently, with different systems, so read across would be so difficult to justify it would be cheaper and quicker just to trial the Mk7 properly, on an opportunity basis during a scheduled trial sortie. Which was recommended; and rejected, again, by non-technical staff. An order was issued that the regulations should be ignored, but a declaration made that they had been complied with. To this day MoD serially lies about this issue, despite the probing questions of various MPs representing the families. (Come on, all this stuff is freely available).
Every single mandated regulation governing Naval Service Mods was breached by this act, yet doing the job properly would have been easier and cheaper (because the NSM was deemed physically non-compliant by Westland, and functionally unsafe by the programme manager - the latter confirmed by the BoI). What the BoI failed to address was the fact the Safety Case was not updated by the IPT when they fitted HISL behind the PM's back. How could it be - there had been no trials and Westland had snagged the installation design.
However, an upside was the RN's renewed interest and support for the Mission System part of the programme (ASE having withdrawn RN support in 1995), epitomised by the superb 849 team at Boscombe. Good guys, let down a little by a rather oblique reference to safety criticality misleading the inquest, when a firm statement was needed as to the content of their IFF MAR recommendation report. (The original one, before succumbing to pressure to retract). That was fixed and made safe in the Mk7, but Tornado refused to, resulting in the Patriot shootdown of the same day. Another story......