1. Avantix Traveller
2. Try booking a fare on NRE with a railcard discount. It will show the Off Peak price at any time if it fulfills the criteria, which I see have changed since the last time I looked.
Avantix Traveller costs money. Customers should not have to pay extra to know the details of the product they are buying!
NFM doesn't show the full extent and details of Virgin's relaxation. If you know it, you can confirm it, but you'd never be able to find out about it that way.
Those saying that "The Manual" is "not definitive" maybe technically correct, but that's not what many rail staff seem to believe. Remember that the enforcement of "rules" (whether actual rules, "company policy" or things made up on the spot by staff) heavily favours the TOCs against the customer. Anything that makes customers better informed is another tool in helping them avoid the traps set by ruthless TOCs. Claiming that it would give the impression that the railway rules are more complex than they really are is complete nonsense, it would just dispel the myth that there is anything "simple" about the railways and possibly (although I don't hold out much hope for it, unless it's accompanied by large price increases) encourage ATOC to make a genuine effort to simplify them.
For all those arguing against its release with arguments like "it's a staff reference", "you can get all the information from NRE/telesales" (fat chance!), "it would just confuse people" and "nobody would use it", please explain why these arguments apply particularly to "The Manual" and not the the RG.