Mud,
The RAF bent over backwards to allow RN aircrew through the system at a faster proportional rate than RAF aircrew.
So they should have done - the RAF already had a full force and was in fact in reduction mode, the throughpput should have been wholly in the RN favour.
But Engines is nearer the truth in this matter. The QFI issue became a major sticking point where the RN operated their Sqns differently but the Senior RAF (AOC 1Gp etc knew it was a means to make the RN force unviable. They also stopped the creamy route and the route for "almost theres" to complete a tour in the Tornado force prior to returning to Harrier.
If there was an obstacle that could have been put in the way, it was. There is shedloads of evidence for this which may be available under foi.