And the drugs........
I wouldn't go near this area myself personally. I remember my underage discos (which wasn't too long ago) and they can be wild. Horny, drunk, emotional teenagers. No thanks.
Maybe contact your local liason officer and the secondary schools. They might be able to help? Also would the venue not be the person to look after the insurance? There are probably strict fire and health & safety regulations alright. And you'd have to have some parents/gaurd/teacher chaperons? I'd start with the liason officer.