Many thanks for your insights. Difficult decision (particularly given a medical condition my son suffers with). He has ENJOYED (and thrived) being alongside a group of children preparing for 11+ exams. An excellent mathematician (outperformed the brightest kids in the area in a recent test) and good a verbal reasoning. English is weak (partly explained by medical health condition and the fact that he simply hasn't read enough (sporting commitments at a national level)), but I feel that if he works at his English over the next two and a half years he shouldn't flounder too much at grammar school. Just make reading enjoyable! Maybe I'm being too optimistic.
NOT an easy decision. Reports of local comprehensive are mixed. He wants good teaching and good learning environment. Small private school would be the best for him, but not best for my wallet!!!!!!! So what does one do?
I regret to say that I'm probably in a minority on this board because I don't attach much weight to "natural talent". Those who do might wish to read "Bounce" by Matthew Syed