I suppose it also depends on what you intend to do with the group? Open a hive?
Suggest an observation hive a better option if available.
risk assessment def required - inc what to do if something goes wrong! location of local hospital ....
those with known allergic reactions to have an epi pen? (perhaps?)
need to check insurances - what and who is covered by what? who would be liable in the event of an accident?
dont think BBKA insurance covers running events?
also check with the school and country park who is actually organising the event? if not your apiary then is I suggest its the Country Park who is the responsible body. Need to confirm this. i think you have been asked to lead an event so in effect a 'contractor'.
PPE required will they need bee suits? are there enough?
school should be responsible for group behaviour and aware/managing child issues like allergies etc..
At no time should you or a volunteer be left alone with children - safe guarding issue and DBS checks would def be required!
you should be able to insist on the size of the group and spilt in to manageable number too say group of six for example. there are legal requirements for adult pupil ratio for school groups but extra help wise... say an assistant beekeeper on hand.
would also ask what are the bees in the apiary like? gentle bees or a bit defensive? worth knowing (which hive to avoid!) and also being aware of weather conditions that might affect temperament !
i have gone into schools... kids loved putting the bees suit on and fascinated handling pieces of wax comb. Also loved watching me light a smoker and then letting them puff the smoke out - with tasting honey at the end... bought a cheap pack of wooden teaspoons. children loved having a dip and i was surprised how many had never eaten honey
☹ so worth asking that!
great thing to do but plan well and make sure you are not personally liable for any mishap.
Steve