Thanks ladies.

TFB, you are right on that his intellectual side and emotional side were miles apart in maturity - I think that has been the main reason for the mega tantrums that we have had over the last couple of years - he could understand but couldn't deal with his emotional response to things.
He has been slow socially, but we have made a lot of effort to take him to all the kid activities around here because I can see that he tends towards being socially retarded like me. He is doing really well now and is very social and chatty and engaging at kindy so I am not worried about that aspect any more.
We do indulge his obsessions, atm we read a few pages of a space reference book for bedtime stories along with the readers. He spied the recipe for making a volcano in a book at kindy and talked the teacher into letting him do it there - bless the mess they make at kindy that I don't have to clean up!

MD, those activity books are a good idea, I might see if I can get a couple of maths ones. I think he seems to be learning words organically through reading so we might just keep going that way. I am not keen on using the computer because he tends to zorb into the ipod etc so I try to limit his time with them. And DD has to be in on the action when he is near anything lol

I am thinking those little counter buttons might be a good idea for maths concepts? He is very visual and logical so I think that might be the way to go.