As promised, I have published my ongoing research into deciphering the code in chapter 55 and nyou can read it at http://www.orffyreus.net/. I haven't actually deciphered anything yet although I feel I have made some small progress in untangling the clues. I confess I've reached a dead end at the moment and although I do have some other ideas to explore there is nothing sufficiently convincing for me to think it worth sharing.
Even if the web site inspires someone to have a go at following my lead and succeeds where I have failed, then it has to be worth it.
Good luck!
JC