OP I think you've done a wonderful thing to even try to change the opinions and behaviour of the school.
Im horrified that there is even still a 'class pet' trend. It's unnecessarily cruel, especially to those two poor buns stuck in that tiny cage.
If they're sent home to people's homes for the weekends in that thing, no doubt that's where they'll spend all weekend at most of the houses they're sent to, purely because suitable Bun dwellings are expensive and take up huge amounts of space - I bet the majority of people who sign up to have them don't even have the bare minimum to suit the needs of the rabbits.
As for the head saying that they did class assemblies - is he serious!?!
Telling a group of young kids how to care for a rabbit in an hour assembly and then leaving it to them to tell the parents is neglectful to say the very least.
The diet these buns has sucks, the living space is atrocious and who arranges and pays for their veterinary care?
Ive been lucky to have had a bonded pair of rabbits, but now that they're both gone over the rainbow bridge, I wouldn't have any more. They're expensive, hard work to keep clean, need so much space, mental stimulation and exercise. They're intelligent, interesting creatures and their behaviour is utterly charming (mine used to binky like nutters around the garden, and one used to dig trenches and then 'mud surf' for hours).
They make bloody awesome pets when you treat them right and allow them to just be rabbits. But they're not pets for kids.
And it's not right for them to be cooped up like that, unable to stretch out, for more than a short car journey (which in itself can make the stressed and susceptible to cardiac arrest).
A school is no place for rabbits, a tiny hutch is no place for rabbits and the homes of people who are ill prepared and unwilling to care for them properly is no place for rabbits.
All that will happen is that these poor rabbits will have mental and physical issues, will scratch and bite the children and will live out a miserable and short life.
As much as the head has a responsibility to the children, he also has a responsibility to the welfare of those rabbits and also to ensure that the children understand about responsible pet ownership.
They're not being shown a good example and using the excuse that that is what they've been told by one person/pet charity is ok, is not responsible either.
If they'd done their proper research before obtaining the rabbits, they would have seen how hugely unsuitable rabbits are as pets for kids, let alone as school pets.
The head should be ashamed of himself.
Well done you Op for making a stand. Keep plugging away and get rabbit welfare on their case too!