I'm the DofE leader at my school, we are out on Bronze at the end of the week.
Things we are doing to mitigate - hats are non'negotiable and if you dont have one, we have spare!
Extra checkpoints with water (although its practice anyway, so checkpoint is never more than 3k away).
Our campsite is really shady anyway, so thats not an issue.
If we were going on Tuesday, I would probably take all the group kit in the van to seriously reduce the weight kids are carrying. Depending on location and transport arrangements (and the hour by jour forcast) start early, have a long break at midday and carry on late afternoon. If it was where I was doing silver a few weeks ago, I would reduce the distance by about 5k.
What we wouldnt do though is ignore the forecast, and we also wouldnt mind any parents checking in with us about our plans. I would be concerned if they didn't change anything.
I would have no issue with my own kids doing an expedition with a group like mine (obviously!) But i have seen many groups out which I would, so I would urge uou to check in with the leaders.