Dear Mary: How can I tell her that her table manners are disgusting?

Q. My mainly male colleagues and I were happy to learn that an attractive young woman would be joining the staff of the boarding prep school where we work. Yet, unfathomably, and despite having gone to the Dragon and grown up in north Oxford, this new colleague’s table manners turned out to be truly revolting. She eats very quickly, with both elbows on the table, head down and lifting the food in via her knife, hardly using her fork at all. This has turned us all off — most notably me at whom she has made a series of unsubtle passes — and as a result we have cancelled the tradition of Sunday staff suppers as no one can stomach sitting at a table with her. The headmaster’s wife is clearly paralysed by the size of the task involved and has no idea how to tackle this young woman (who is a competent teacher).