He doesn't interfere with older/bigger kids but will happily rugby tackle smaller toddlers or even hit them in the face or pull their hair
I was mortified when he did both of these things to a smaller girl who also appeared to have SN at a playgroup. She got very upset and had to be taken home. I hesitantly let him go up to her again after the rugby tackle as I thought it was just one of his over enthusiastic hugs, but then he hit her in the face! I don't know what to do other than not letting him interact closely with smaller kids, it's really hard to intervene without preventing him from socialising completely...
Any advice? I don't want him to become that kid that other mums don't want their toddlers to go near him!
You have to watch him like a hawk ready to get inbetween your dc and other kids at a moments notice. You may even have to follow him round the playground, one or two steps behind. If he whacks anyone, you immediately take him away from the situation and VERY firmly tell him "No hitting. It hurts!" Don't bother with long explanations. He won't understand. If he does it again, you take him home. It probably won't make any difference until he's 2 1/2 as he won't be able to control himself. If its too hard for him to resist, you may have to leave off playgrounds for a while.
He's not a bully. He just can't control his impulses yet and doesn't understand that what he does hurts. He probably finds it pretty interesting to see what happens when he hits others / pulls hair etc.