When I did my IR at BAe Prestwick in 1995 there were several RAF ME students doing essentially the same course; their graduation test was to be an IRT, but carried out by college standards instructors.
Several of them asked the resident CAAFU examiner if he could come along (for the usual fee of course); he was willing and the plan was set for them to get their CPL/IR issued while still in RAF training. Unfortunately the RAF (I don't know if it was CFS or MEFTS) decided to send examiners along to audit the tests. An extra civilian in the aeroplane would have aroused too much suspicion, so the IR idea was dropped.
I have no idea if the experiment of sending MEFTS students to civilian schools for IR training was continued.