I agree - I'm afraid that comparing the outcomes at two different schools won't get you anywhere, however strongly you feel about it!
First you will probably have to overcome the fact that there's already been a review, and you can only do this by arguing that the process
was not 'fair, consistent & objective' - not by disagreeing with the panel's judgement
This is the sort of case you could be up against:viewtopic.php?f=12&t=31963
and this thread will help (although it was written for the 11+ reviews):viewtopic.php?f=12&t=31030
If you win the argument over whether the process was 'fair, consistent & objective', then an appeal panel can take a fresh look at your case for selection.