Thanks for your email. I think the advice in the Q&As fits your circumstances very well.
If DS was just a mark or so short, it's possible no one will be bothered about extenuating circumstances.
In any event, the advice tells you what to do, whether or not the question is asked:
If your extenuating circumstances are not too strong (in the sense that there isn’t any evidence at all to show that your child was affected) -
….. in this situation the best approach is to appear reluctant to ‘offer excuses’, to let the panel drag the information out of you bit by bit, if the opportunity arises, rather than to build it up as a major issue. Understate the point, or you risk diluting your case as a whole.
For example, if there was a minor disturbance during the test, but no evidence in the invigilator’s report, I suggest it’s best to say little or nothing about this in your written submission or in your presentation. Someone is almost certain to ask during the Question & Answer session whether anything might have affected the 11+ result, at which point you can provide a brief explanation, adding: “I wasn’t sure how much this could be taken into account as there doesn’t seem to be any hard evidence ….. I do understand that some distractions in an exam room full of 10 year olds is inevitable …..”
There might be a lot of sympathy on the panel for this sort of reasonable approach. The mistake most people make with extenuating circumstances is to overplay them – much better to underplay them!
In the unlikely event that no one asks a suitable question, and you sense that the hearing is drawing to a close, then you would need to take the initiative and say “I wasn’t sure whether to mention this, but ……….”