Would it be worth sending a cover letter?

If it was notable then your school will have told the exam boards, who will have looked at it and given special consideration if necessary. So it's already been taken into account. Essentially a letter would just be trying to get double credit for one problem.

If you must, ask your referee to include it.

Stop trying to milk the system to up your marks.

Yes it was pretty notable as I had to go to A+E which was really fun I can assure you. I just wondered if it would be better to inform them as its a condition which is likely to return and affect me from time to time and I wondered where on my application it was best to include this.

No, you weren't wondering that at all.

If you were, your post would have been "shall I tell them about this illness which is likely to reoccur?" not "omg feel sorry for me as this happened in my exams".

Sugarcoat it however you like but the admissions tutors will see through you.

Ever the cynical one aren't we

Yes they can feel sorry for me if they like, everyone likes a bit of sympathy every now and again. You know I think I might just send a huge card to them saying PITY ME. Maybe I'll call them up and cry and write a personal statement all about my problems and how they make me feel....