Although I cannot advise re secondary or boarding, I have recently made the leap across the divide from primary to an independent day school. I am VERY happy. For me the biggest improvement is concentrating on teaching and learning - not on unproductive paperwork. I am working hard, but it feels so much more worthwhile. The relationship with parents is obviously different. Working hours are officially longer, but I am beginning to reclaim my life. Terms and conditions of employment vary so much from school to school that you will have to examine them closely - no burgundy book in the independent sector. I am sure that others will be along with more experience and advice specific to your situation Good luck.