hey, very very best of luck
I'd suggest you don't need to put your school down.
I would make a virtue of your long employment in one place. This is proof of loyalty and a desire to stick to a task and get it done, proof that you've enjoyed working as part of a team. It's only now that you've decided you need to be stretched a little more and look for new challenges. You know, biased bullshit that puts you in a good light.
If you have ever done any sort of voluntary work, helping out on an office give n gain day, a charity run, made soup for feckless tramps 6 years ago, anything, big it up like your Princess Diana but with a soul.
If you have any sort of exclusion orders, if there are parts of town with schools where you're not allowed to loiter, no need to mention that.