On what grounds could they be taken to court, though, and by whom? PRH has made money from the book, so they have no ‘loss of earnings’ case. There were a couple of lawsuits started in the US by readers of James Frey’s A Million Little Pieces, but as the publisher settled so quickly out of court (because cheaper), it’s not clear they could possibly have got anywhere, even in a very different legal system. If your legal case is that readers wouldn’t have bought TSP if it had been labelled as fiction rather than memoir, so it’s ’false advertising’ then you’d have to prove those readers only ever read memoir.
PRH might ask RW to repay the advance for OWH and cancel it.
I’m talking about the book side of things — I know nothing about film, and whether the production company might have a case.