This is disinformation.
Rowling may be an awful person but she bought the yacht in 2023. He was long dead. The yacht may have been a ferry to his island but she wasn’t the owner at the time, and it wasn’t for hire or a shell company.
There’s no evidence that she approved or was involved in the invite to the show either. Rich people have assistants for this sort of thing; they don’t want to be bothered (on their estate) by some other rich person asking for tickets to a show they had someone ghostwrite.
