I have a vague recollection that about 3 chaps on 13GE went straight onto the Mk5, despite never having flown before?
It was in the period when the Mk3s were going to Warton for conversion into 3As and the system was trying to rationalise how best to use the fleet without excessive training delays.
But they coped OK.
There used to be a trip known as the 'conversion handling check' to assess whether a student was ready for the Mk5. But it was early in the course and wasn't a reasonable test - indeed, one chap was nearly chopped after doing rather poorly.....
....but he later scooped the top pot at ETPS and became a top TP. So much for pointless early assessments!