Boys' school, principal called "The Fish"?

[soundofsunlight]

The story is set at a boy's boarding school. The school is not doing well financially, and might be in danger of closing. So, some of the boys come up with the idea of setting a world record for highest tower of soda cans, to get publicity for their school and save it from having to close down.

There is a girl's school across the road, and they are going on a field trip to a city, so a couple of the boys stow away on the school bus to collect soda cans. The girls manage to hide them on the way there, but when they return, the boys try to sneak out the back door of the school bus, which is an emergency door and sets off an alarm, so they have to run for it and leave the big garbage bag of soda cans behind. The girls' teacher demands an explanation, so the girls have no choice but to say they want to beat the record for highest tower of soda cans, and they end up getting the publicity instead of the boys. I don't remember how it ends.

Other details: The principal of the boys' school has a name like Mr Sturgeon or something, and the boys call him The Fish. I think one of the boys also hosts a radio program for his school?