In reply to Just Tintin:
Writing a risk assessment shouldn't be terrifying! When it's done right, it should help you understand how you are going to manage your group in order to reduce the risks. It's only the (largely mythical) influence of 'Elf'n'Safety' that makes it intimidating.
I could email you some of mine to look over, but honestly I think 90% of the point is in writing it yourself - that's what makes you think about what you're going to do.
So, try this: divide your day up into parts. You're probably going to want to think about transport there, the walk-in, the actual climbing part, and managing slack time (ie when they're not climbing, so lunchtime, when you're rigging, etc).
Open up Word and create a table with 6 columns. For each part in turn, write down a list of what could go wrong - ie what are the hazards?
The write down how likely each event would be. I wouldn't go any more complex than High/Medium/Low/Very low. And then how bad each event would be - the severity. Again H/M/L/VL is fine.
Then - and this is the important column - write down what you're going to do to reduce either the likelihood of each event occuring, or its severity, or both.
The note down the new likelihoods and severity, now you've implemented your control methods. As long as no event is more than medium or high likelihood AND severity, you're probably fine.
So, as an example of one complete row, there might be an RTA in the minibus on the way there. Liklihood is low, severity is high. To control it I will make sure all the kids have their seatbelts on, the driver will have passed the minibus assessment, perhaps a second MoS will be there to stop kids distacting the driver. Now the severity remains high, but the likelihood is very low.
Do this for every hazard you can think of, and you've just written a risk assessment. And it'll be much more specific to your day, and much more liekly to be followed, than if you'd just downloaded one. I'd far rather someone gave me a personalised RA that they've put thought into.
A few things not to miss - effects of heat and cold and thirst, especially if the destination is out of the way. Minor scrapes and cuts (many times more likely than a big fall). Protecting kids from rockfall during lunch.
Have fun! If you want, I can have a look over when you've done it (if you haven't guessed, this used to be my job).