Says what it does on the tin...intercranial bleeding has always been an immediate rejection. I believe, but could be way off on this, that there is a risk of further bleeding due to concusive forces caused by munitions in training/war. They won't want to take the risk.
Appeal, appeal again and then appeal some more. Mate, bad luck on that one, that must have been sickening and, from my own experience, bang out of order. I suffered multiple skull fucktures / spinal injuries in a really nasty injury which, whilst putting my application on hold never stoppped me joining. Maybe I got a sympatetic MO on the day, there appears to be little consistency in medical decisions. Age may be a consideration I believe, apparently we kids heal pretty rapidly, I have no idea how old you are.
4 years on I have no med complications from my injuries, except some of the shit I spout on here I pass out (not literally - that possibly would count against me!)and commision shortly (touch wood)and so seriously, keep shouting on this one.
Good luck, feel for you very strongly on this one and if I can help in any way PM me.
PS you certainly sound switched on enough for special forces. Most arrsers wont' be intelligent enough to have heard of Fostoyevsky, let alone which team he plays for
Alternatively they could take a punt on the internal bleeding and knee damage, and run the risk of having to pay out in perpetuity if you pop a blood vessel or your leg drops off.
To a grerater or lesser extent, the army can choose those without (or with fewer and less complex) potential health issues, particularly for specisl needs recruiting. Sorry to be brutal but that is simply the way of the world. It's not 'unfair', just common sense.