E L James may tie up S&M-loving readers yet again by revisiting the characters from her “Fifty Shades of Grey” novels in a second trilogy. A source close to the British author, whose real name is Erika Leonard , tells us that the self-made fiction phenom is considering rewriting the best-selling trilogy — “Fifty Shades of Grey,” “Fifty Shades Darker” and “Fifty Shades Freed” — from the per…