I've been in the same positions with three schools my kids attended whilst growing up. Granted it was a good few years back, but I didn't apply for any licence or insurance etc, and I was never paid. All that was done in advance was a note went home to each parent advising them of the day I would be bringing the snakes in, and gave the parents the opportunity to register any objection to the child being present (none did). On the day we started of with a Corn snake, then an adult royal, and we gave the children the opportunity to come up after the "formal" talk to touch and feel the snakes. On two occasions we would take our large boa, but made sure all the kids (age groups were 4-6 and 6-8) sat still and didn't rush up to us. Mind you the boa was puppy dog tame and was easy to handle, so I was never too worried if two or three excited kids wanted to get closer to her.
Back then there was no formal agreement or disclaimers etc that was signed. It was just common sense. I also did a similar presentation around the same time for a group of cub scouts, and that was pretty much the same lines. No formal paperwork, no insurances etc. The kids were all told that if misbehaved then they would be left on the side line of the next games night or some other deterrent

- But that was before the days of compo with people claiming the experience caused their little Jonny so much distress and nightmares so seek financial payment.....
On one occasion at a private nursery I received an invitation to attend a 7 year old's birthday party to bring a snake with me (she had seen how interested he son was in the corn snake I brought in with me that afternoon)... I turned up on the following Saturday afternoon with an 8' boa in tow... but the kids loved it. We all sat (about 6 kids and two adults) down on the dining room floor with the snake stretched out allowing all six kids to pat and touch the snake. The snake just laid the taking it all in, showing no intention to get away form the attention.
Naturally we made sure that anyone who came into contact with the snakes washed their hands after, and the visits were done in the summer term so there was less of an impact heat wise.
My advise would be to speak with the teacher and the headmaster / headmistress and discuss what concerns you may have and equally answer any form them. Then its a simple case of arranging the date and to what level you want to take it (hands on or just a talk). Its events like these that help put our hobby in a good light, and educate the kids (and even the parents) on the good points rather then negative publicity. When I did my first presentation at my sons nursery, probably late 1990's the school ah notified the local press and we had our picture taken with two of his class mates and the boa centre stage
