No idea, but you could try contacting
Aviation for Paraplegics and Tetraplegics or the
British Disabled Flying Association (formerly BDFC) both of whom are very knowledgeable in such issues and can almost certainly point you at chapter and verse.
Sorry to hear about the loss of medical - hope you're managing to continue something interesting in the aviation line. If you find yourself back in the UK and want to talk about test flying non-aerobatic sports aeroplanes, give me a shout. (No money in it, but a good alternative to real work.)
G