My son has the same problems,as he is small. But not as small as your boy spud. He had a terrible time in his last year at primary,not just because he was small,but because he was/is bright aswell. I think it all depends on the child,and how they deal with it,and of course the support of the parents/family. This huge bully actually kicked him in the chest and marked him while he was playing football. The parents were the sort who think their son is perfect,and no way would my son do that, sort of attitude. The police were involved etc..It was a nightmare. This is why i decided to apply to an independent school. There has been one incident where there was some pushing and shoving, it started at a party,then carried on into the Monday at school. My son is actually a friend of this other boy. There are three of them who hang out with each other at school. Both my sons form tutor and myself both agreed that maybe the three thing was a bit of a crowd. Everything is fine now. A bit of pecking order maybe,but the school is hot on the bullying thing. In their first assembly it was the main topic! There are bullying boxes and prefects who the shells(yr 7s) can go to. The bullying boxes are for the children to post a note if they feel they are being bullied and cannot go to anyone.
I always tell my son that, because he is small does not mean he has to accept the way some people want to treat him. I say things like all good things come in small packages, and although he may not excel in sport(he has perthes desease) he makes up for it in other ways. He has an excellent mind. We have to just be there for our children, and help them develop the backbone to get through life. My child is confident and is doing well in his new school. Of course it is inevitable that there will most probebly be other problems,but we are there for our children,and they will grow up to be successful adults...Albiet small adults. All the best spud,to you and your wonderful small son. PS.It sounds to me that he is mature and feels he wants to deal with it himself. Sometimes we are afraid as parents for them to do that. Just take a back seat sort of thing,and let them work it out themselves. As long as they are happy and acheiving. We know when our children are not happy and when there is something wrong.
Then of course we will stand with them and support them through it.