They have. I think they were for use when the Harrier was the seagoing jet of choice for the Brits.
Harrier still is the seagoing choice of jet for the RN. The GR9 is going to be flown from the QE Class until the F35 is sorted.
Incorrect. Angled decks were being used by the Royal Navy when Phantoms, Sea Vixens and Buccaneers were the aircraft of choice.