Following my departure, I think I should add more to this.

Are you suggesting handover notes were essential to looking after your students? Even though the school knew months before I left there was no replacement there to take over from me. When I did meet my replacement later and asked if he'd seen the handover notes I spent time writing I was told he never saw them. Glad I spent the time trying to make sure my students were looked after, but clearly it was pointless.

Correct me if I'm wrong (and ideally without naming names to protect the guilty/innocent), but three teachers have left before the end of their contract in the past two months. I'll leave it to the readers, assuming there are some, to consider why they'd do this.

To give you space to vent your feelings, the only teachers that leave Shane so easily are those that the school no longer wants; the ones who are told to leave (but not sacked, obviously). If Shane likes you as a teacher they'll do whatever they can to make you stay there. Personally speaking, I spent three years working there but still didn't receive a reference letter that I needed for my next job when I left. Surely if I was bad enough that they wouldn't give me a reference then I couldn't have worked there that long, but I did and have the pay slips to prove it. Perhaps they just didn't want me working somewhere else that might possibly have taken their business?

As the OP said, there are better places to work.