What age is he, Kerrymum?
When kids are young, I don't know that it's all that madly important, to be honest, that they're intellectually stimulated all the time at school, as long as you can do it at home, and they're getting something, probably social skills, from school.
I speak as someone who was also in the 99th percentile or above as a kid. Looking back, I'm glad to have had a fairly normal childhood, not been pressurised or cut off from my friends, who are not officially G&T.