My wonderful beta reader, Marcia, found that I had inadvertently changed 'Marco' into 'Mario' for several pages and then changed him back again.
I sometimes have to comb through the book to find out what I have called a character. I had two people called 'Lizzie' in my latest book, Lord Philip's Christmas (to be published 2 December). One has now been rechristened Sarah.
It's so easy to do and one of the banes of my life. Nonfiction authors should not have the same problem - their people were alive in the world and not in the imagination. Perhaps I should return to straight History. I've often thought of a biography of Queen Adelaide, wife of William IV. One day perhaps.