Prof,
I think you are wrong in laying the blame on the JHC. This organisation is an umbrella org for the 3 Services to coordinate the ops of battlefield helicopters and 16AAB. Whist they do coordinate the standards (min currency hours etc) the single services have right of veto for their own people (ie retain Full Command). I think I am right in saying that the min hours applied is the RAF minima rather than AAC or RN.
Basically each Service is responsible for the standards of professionalism of their people, the dilution of expertise is an excuse IMHO. If there is a concern about dilution then amend the standards applied to compensate - what was the Sqn QFI/CO/Force Cdr/Group doing about this? Dixon covered this but hedged too much at the higher level and tried to spread the problem to the other Services when it was largely his own that was the problem.