When I joined a long time ago I had a PPL with about seventy hours including some rudimentary aerobatics. Most of my contemporaries at Linton had been in the UAS and were streets ahead because of the training they had received and they were far more comfortable in the service environment than I was in that first couple of years. All that being said, one lad on my course with zero flying experience upon entry went on to fly Jaguar and Tornado. I seem to remember the old adage PAD for preparation, application and dedication - hack that and a PPL is unnecessary !