I run a school trip every year and organise everything myself. I usually largely overestimate cost to plan for any potential problems. Up to know at the end of the trip I have refunded parents with the surplus. This year again a considerable amount of money is left in the budget. I was planning refunds but the Head has now informed me that the money will be kept to cover "staffing cost". I feel this is very wrong and wonder if anyone had had a similar situation or maybe knew of any rule regarding this? ( a previous year I had to do a ridiculous amount of paperwork to refund £3 per child because we weren't allowed to keep the money....).