https://www.atoc.org/retail/_downloads/NFM/sectiong.pdf
Theres my favourite bit, Section G, which includes rail rovers...
(via this link you can actually access the fares, if your change the bit that says "section g", and then but in say, "sectionb", but the trouble is you need to know the exact page numbers (which i dont), so it would be ..../NFM/sectionb-pagesxx-xx.pdf (so if someone has a printed copy of the NFM (available at all good bookshops for £15 afaik), and they will be kind enough to release the page numbers, that would be nice. I only have a local current manual, so I cant help unfortunately.
For all other sections, the Nat Rail link is:
http://www.nationalrail.co.uk/passenger_services/manuals.html