I think the argument that there was only one supplier only holds good after the decision was made to upgrade Nimrod. Clearly, the original programme permitted, but perhaps didn't encourage, the concept of a replacement aircraft (hence, "RMPA").
What I'd want to know is this. Were the decision makers (presumably including the Equipment Approvals Committee) made aware of the primary technical risks mentioned above? I know exactly what routinely happened in that MoD(PE) area. A Financier would be wheeled out and he'd assure the Gods that he "knew of no technical obstacle". While strictly speaking a true statement, it would still be a serious offence (misleading by omission and/or commission). The engineers would be left seething. For example, in March 1999 I was actively prevented from briefing CDP before he went in front of the PAC. I was the manager of one of seven programmes warranting their attention, but a non-engineeer who knew nothing about the programme and had never worked on it was told to conduct the briefing; without being briefed himself. (I found this out after the event and asked for the PAC to be given a clarification paper. Request denied. I submitted it anyway, but believe it was blocked). The result was CDP's evidence was complete balls. I was told there was no way I would be allowed to tell him the truth.
BTW, this was the same PAC session at which CDP agreed the Chinook Mk2 remained in the same (unairworthy) state described in the 1992 CHART report. He admitted that, so you can imagine what was omitted!
The single source argument only holds good after this decision on procurement strategy is made. Fine, I can understand the MRA4 PM's position. There comes a time when, assuming the decision is based on true and complete facts, you have to accept the Gods have made a decision - but that decision should be explained to you. It seldom is. For example, at the same time RMPA was being decided, I was informed a 2 year competitive tendering exercise was to be cast aside and a major contract awarded to a company who had never bid in the first place. From that day forth, the entire focus of Risk Reduction was aimed at compensating for having an incompetent prime contractor foisted on me. Not entirely incompetent, but they concentrated resources on 30% of the programme, completely ignoring the rest, largely because they had no track record and no understanding of such a programme (which is why they didn't bid in the first place). The programme was successful, but despite the prime, not because of him. So I understand the dilemmas the Nimrod team faced.
But having that decision imposed on you doesn't mean you just blindly dig deeper holes for the next 15 years. You follow the rules, conduct the periodic Reviews, report honestly and offer your best advice when seeking decisions. I'd want to know when the PM advised the 2 Star that the procurement strategy, indeed the entire programme, was no longer viable. The answer should be - no later than publication of the NART report in 1998. It contained enough evidence to stop the programme in its tracks. It may or may not be coincidence that the major slippages commenced around that time - certainly, anyone reading NART would twitch violently and seek a long hiatus while he reassessed every part of the programme. I sincerely doubt if NART was ever mentioned to the EAC, in the same way CHART was withheld from all concerned with Chinook. But there were previous reports from 1994 and 1996 directly relating to mainplane construction. Were these considered by, or even show to, the MRA4 team? It needs and warrants an inquiry. Too much money has been wasted and capability lost.