I feel duped by the headteacher
A: Most people start on M1, but a few are started higher up the scale in recognition of "relevant" experience. This is at the discretion of individual governing bodies so there are no hard and fast rules. Your headteacher should have explained why your experience didn't merit starting at M2, but I don't think there's much point in kicking up a fuss. A 46-year-old mother of four with 20 years of rich experience as a nursery nurse and a first class BEd assumed that the school would pay her more, but they didn't. I can't understand why you're not in a union and hope this experience has made you join one.