Hi Kb70
I would check out the free downloadable resources in My Hedgehog Street https://www.hedgehogstreet.org/my-hedgehog-street/free-downloadable-resources/
and see if there is anything you can use.
Maybe you could try to make contact with a Biology or Science teacher and that might be a useful contact route. I don’t really know, but maybe you could ask for an appointment with someone. I somehow suspect that talking to someone might have more effect than trying to explain it all in an email. An email is so much easier to ignore. But you could email to ask if it’s possible to speak to someone (Science Teacher … ) about hedgehogs. Or is there a School Secretary that you could speak to initially to get an introduction to a Science Teacher (or do they call them Lecturers in Colleges!)
Alternatively do you know any parents who could make an introduction?
They might not know about the hogs and be really pleased they are there – you never know your luck! But a one to one conversation with someone sounds to me an easier way to start.
I would be inclined to try to get them interested in the hedgehogs, how lucky you all are that they are there, etc. before tackling the litter issue (and of course the netting) i.e. that is part of helping to look after the hedgehogs and their welfare to make sure the nets are lifted up and the rubbish removed. Explain the dangers of litter to hogs. Maybe they could start a Hedgehog Club.
Someone else may have some better ideas, but good luck, it sounds a really worthwhile thing to try.