The British Royal family knew they had a leaker, but did not do any investigations until now (if they have). Some of the examples: Sussexes leaving, information on nannies, Beatrice's wedding, Sussex move to LA. This should have been a huge security concern (safety of H&M included). Unless someone high up okayed it/relased through their staff?
Dan Wootton (The Sun) had details about a particular story that was hinted at, but not mentioned again. He killed the story for other exclusives. Then all the leaks began, he even had the exclusive papped family photos of the empty commercial plane trip to Scotland). Dan wasn't even the royal reporter/editor, but became it after this. It was Emily Andrews and she had to leave (essentially pushed out, she got a job at the DM after six months).
It seems like Harry may have given false information to BRF members to find out who was leaking. Emily Andrews printed the wrong date for the baby shower. She had been given the false information, she insisted that it came from one of the royal offices.
Now there is proof that The Sun paid the partner of royal staffer Christian Jones (current Communications Secretary) for stories. It was said that CJ was a Sussex hire, but he wasn't. Remember when CJ was papped with Meghan? She didn't really get papped otherwise. It was also at the time of Prince Philip's accident.