He has chosen that the police don't investigate this
This is possibly the most ridiculous thing on this thread and that’s saying something. There’s no way, however royal he is, that he gets to choose what the police do or don’t investigate.
Do you genuinely believe that that's what would happen in practice, though? IF the Queen had committed an appalling crime, do you honestly think that anybody in the police would put their head above the parapet and pursue it? Really? And PA is one of her own.
I thought the same thing about the inquiry into Diana's death, where some people were accusing Prince Philip of having been culpable. It was officially found that he wasn't involved, of course - but IF he had been found to have single-handedly planned and executed the whole thing himself, would YOU have been personally willing to go public with it? The police, however high-ranking, are just people too.
Gently advising PP to stop driving at his great age following a relatively minor car accident is one thing, but IF he had done something truly despicable and far-reaching....