My son was at the hall for years one to three, leaving about 2 and a half years ago. It is an excellent school but it wasn't right for him and he was miserable.
Year one was fine. Year two, when they started cursive handwriting was a disaster: he and we were told that he was lazy, becoming naughty, wouldn't engage etc etc. He felt himself right at the bottom of the pecking order and was depressed. He would say things like "I'm stupid and I just want to be dead".
His teacher the next year helped; but it was not until we insisted on reference to an ed psych that he was found to be dyspraxic and to have specific learning difficulties. He has an IQ of over 135.
The focus is on the top 25% of boys who are fabulously able. One always gets the feeling that the rest make up the numbers rather.
Lovely boys. Generally very nice parents, although quite pushy-lotsof Kumon maths, early morning violin lessons etc.. You need to be available to do quite a lot of academic support.
If your son is an easy high flier, then the Hall will be perfect for him and by the time he leaves he'll be practically ready for A levels. If he's not, then think very carefully. My son is now at a school which is still pretty academic but has a much more rounded approach; but he's boarding, not in London