Twix - can't you sleep?! Neither can I! Please don't say your son "only" passed by 2 marks. He passed and that's what counts. I know from experience that, just as end of Yr5 levels are not a very accurate guide to 11+ performance, 11+ scores are not necessarily a very accurate guide to how a child will perform at GS. ds2 passed the 11+ by not a very great amount a couple of years ago - he is now in top sets for everything at his GS and gets excellent reports - better than ds1 who passed the 11+ by a very big margin
Good luck with whatever you decide to do.