hi loulou
My son started hitting and kicking in year 3 always when some kid had done something to him like name calling or taunting. This continued through year 4. We and the teachers were constantly telling him to rather go and tell the teacher if someone annoyed him. We even made him some football cards which he could show to a teacher (white meant he felt ill, yellow meant he felt annoyed and red meant he felt angry)
this saved him having to speak when he was stressed out. He only used the white one but I think the cards gave him another option other than hitting or telling a teacher (which was too difficult for him). Currently he's in year 5 now and he hasn't hit anyone this year and he's gone and told the teacher when he's feeling angry. He has had a lot of praise from all the school staff for this and this has reinforced the communicating bit for him. It can be very worrying when they do these things. I still supervise my son quite a bit when in group situations.
Dayle