Andy, apply! You need to update your CV anyway. If you get called then go, sus out the job and be honest with them. Unless things have changed since I left teaching (which they may well have done) they will ask if you still wish to be considered for the job before they offer it, so keep your options open.
Remember, not long ago you were a bl66dy good teacher and you still are. It is obvious to me that you are not being given the time for the management responsibilities, and you seem to have had more than your fair share to deal with in a difficult time for teaching (when wasn't?).
I gather Dom has seen the news that Derby is to get trams. I wonder if he is suggesting a change of career!
#Ed