The head (who's only been there a year) highly apologetic, and said there was no excuse. But she has been fighting ingrained habits, and poor procedure. She'd assumed teachers were following the procedures, getting back to me, etc, and that the midday assistant was trained, and both turned out not to be the case.
We got her to promise to speak to the parents of the offending children, speak to his new teacher, and designate a 'safe' adult for Sam to be able to talk to. I said that if there was even a whiff of it still going on when we go back in September, he'd be out of there, sharpish.
I also said he's a bright boy, and will be fine academically, but would rather his pastoral care was higher priority than the neatness of his handwriting. Go me!
He has the option of swapping into the other reception class, but not sure how much that will help as they'll all still play together. Might break the cycle, I guess...
It had always seemed mildly shambolic, but he seemed to be learning, happy and safe. If the latter two turn out not to be true, I don't want him to be there any more.