dangermouse, there's a lot of sense in what you say, but there're many key misunderstandings as well. (Obviously, I'm ignoring your mischevious stuff!

)
"Test once, use many times" - too right! Truly Combined Test Teams (CTTs - which is the wrong name, because you need a proper evaluation element too, which will probably include lots of non-test work) are very much the way to go, but unfortunately for whatever reasons attempts over the last several years have only made limited progress until fairly recently.
Some of those reasons have been very parochial, others more understandable. The incorporation of HATS into 206(R), and FJTS into 17(R) & 41(R) should be a good start - so long as all concerned do not forget that the tps are only part - albeit one of a few essential parts -of the Aircraft Test & Evaluation
Collaboration. (ATEC).
Speaking of ATEC, you say:
Originally Posted by dangermouse
The specialists at QQ do not have the operational experience necessary to evaluate operational worth (and neither do the contractors), that's the OETUs job
As written, that's true. However, it doesn't recognise at all that the QQ specialists do not work in isolation at any level - they have the ability to draw on/be guided by the tps (of course), but also the substantial number of AWC military personnel who also function as embedded SMEs throughout the T&E work done at Boscombe.
Now, of course, the Test & Evaluation Squadrons (wot's an OETU?

) can call on that expertise, and the ATEC can call on the TES' - see what I mean about a good start? Closer working with the manufacturers is also making headway from all "sides", which is nice.
Other comments:
Originally Posted by dangermouse
But the big difference is that QinetiQ do not certify the airworthiness of the aircraft, they provide recommendations to the relevant IPTs who are the authors of the RTS
Yes.
Originally Posted by dangermouse
(and are free to ignore it as they see fit)
No.
They are required to justify their reasoning, it's far from "freedom". Tucumseh and others have explained what they should be doing in some detail in other threads on the Mil Aviation forum, of course.
The role of QinetiQ at BD is the same as the CAA, AIRWORTHINESS issues only (ie does it meet the requirements of DEF STAN etc)
It's not
quite the same as the CAA; come for a visit and see. More importantly, though, Airwortiness most assuredly doesn't mean simply checking that the requirements of "DEF STAN etc" are met; there's rather more to it than that, as contemplating the implications of the JSP definition of "airworthiness" will reveal.