There was a very neat table out last year which I now can't find which split GCSE results by race (broader groupings than this report), sex and FSM/non-FSM.
It was obvious that for almost every comparable group, rich trumped poor, girls trumped boys, and non-white trumped white. So a non-FSM south-Asian boy would do better than a FSM south-Asian boy, or a non-FSM white boy, but worse than a non-FSM south Asian girl.
The exceptions were the Chinese children who did exceptionally well regardless of financial status, and the non-FSM black children who did a little worse than the non-FSM white children, (but I suspect that the latter is attributable to the fact that "non-FSM" is a very broad-brush measure of wealth, and the results might reverse if you split down properly by family income quartile).