POllyanna -- our older child (ASD) went in his yr 6, but we had to go too. He travelled separately, did the daytime activities (with help split between us and a school TA) and came back to us for the nights. I suppose that was illegal discrimination, really, as they wouldn't have taken him without us (but he wouldn't have agreed to go, so the point is moot).
We did insist that the other kids had authorised absence from school so we could make a family holiday out of it, though. We all had a lovely time -- legit term-time holiday, and (TBH) a break for the younger two from their brother's problems, which were pretty heavy at the time.