The MOD was unable to write a spec worth a bean. You might as well said we need some simulators to train the crew, once you've built them we'll tell you what is or isn't any good.
I can't speak for what the RMPA office was told to do, but the policy of that MoD(PE) Director General (2 Star) was that project managers were NOT to contract anyone to write specs for simulators or trainers. If you didn't have anyone in the team to do it, tough. On my programme, at the same time, no-one had a scoobie (including myself), so I "contracted" Boscombe to hire recently retired aircrew as consultants, and bury the cost in "materiel". When the Director sought reassurance I was not contracting anyone to specify the trainer, I just said yes. If I'd have followed his instructions, the aircraft fleet would still be parked in a hangar somewhere - not unlike Chinook Mk3 (same 2 Star).