To be honest, I can't say.
It's possible that another parent could come along with a score of 340, and (among other things) argue "Please take into account what a tragedy it would be if my child was denied the opportunity to achieve his potential at this school, missing out by such a very narrow margin
It's then up to the individual panel to decide what weight to give to any particular bit of evidence and to any particular case as a whole.
You can try to counter this possibility with "evidence of academic achievement as well as evidence of extenuating and mitigating circumstances as to why he 'bombed out' so successfully!
Be very cautious in how you go about presenting extenuating circumstances - read all the Q&As on this topic, starting with:http://www.elevenplusexams.co.uk/appeal ... cation#b10