In Sense and Sensibility, the man who jilts Marianne Dashwood is called John Willoughby. Yet she and her more careful elder sister and their mother consistently refer to him as ‘Willoughby’. This strikes me as strange. One would have expected ‘Mr Willoughby’, and, on a much closer acquaintance, ‘John’. Was it common in the early 19th Centuries for genteel ladies to address male acquaintances by their surname?