Natalie Dormer is renowned for playing women who mix sympathy with ruthlessness, including Margaery Tyrell (“Game of Thrones”) and Anne Boleyn (“The Tudors”). And that’s how she nabbed her latest role as Hester Appleyard in Amazon’s “Picnic At Hanging Rock.” “[Showrunner/director Larysa Kondracki] won me by writing me the most incredible letter,” says Dormer.