I can confirm Noreen's bit about a police check not being obligatory. I work in schools in the way we are talking about here, and I have actually been police checked, but we also take in other musicians who havent. The criterion is definitely(at the moment) whether you are working alone with children. And you always get a rteacher thrown in if you work with a class, in my experience. In fact I would insist on it.
    I think it is the school holiday dates that is going to make this project difficult, Animaterra. However, if you would like me to try your scheme out on an education person, do PM me a bit of factual stuff on what you've been doing and I'll pass it on to a relevant schools person here and see how they react.