I dunno how often we went back to school on Easter Monday... it happened every time Easter was late. OTOH, when Easter was early... I remember visiting friends in England one year in around 1976, early April, and being asked "How come you're on holiday?" I replied "Easter holiday." "But Easter was ten days ago..." "Yes..." Then I explained. Dundee schools' Easter holiday was always the first two weeks of April. If Easter was early the non-denominational schools got Good Friday as well, but the Catholic schools didn't, to make sure the kids went to Mass.