My dd (year 8) is very good at maths, at her recent target meeting it was suggested that she could do a gcse in maths at the end of year 9.(She wouldn't be the only one out of a class of 16.) The only other maths the school do is statistics. So she would have two years of not doing "real" maths before taking a-levels, in which she will probably carry on with the maths.
I have heard of the higher fsmq qualification offered by aqa and wondered if it would be worth doing all four papers fsmq at higher privately before moving on to the advanced level. or if we should move on to AS maths but this might cause problems at sixth form if she is doing an A2 with 3 AS levels. 