They would not undergo PDA assessment unless Red1 and the chain of command were confident they were ready. If they ever do fail PDA then I presume it is rescheduled until they are up to the required safe standard. As well as causing red faces, that will involve cancelling early public displays and finding somewhere where the weather is dependable to continue training as the Cyprus authorities limit the number of flying days they can have at Akrotiri. The consequent expense would be eye watering.
So achieving PDA really is a major hurdle and stresser for all involved, team and CoC, but particularly for the new guys. That is what this film set out to show, and it succeeded admirably in my view.
Well done the Reds! And well done the BBC (for once)!