The Routeing Guide is anything but simple. It used to be when it was introduced as a paper document back in '96, then they had an over-elaborate online version with multitudes of routes not previously allowed (and some that defy logic), but even that was easier to follow than the current pdf format.

Thanks for explaining I understand it now just hope I can explain to a ticket inspector at Sheffield that my ticket is valid.

The ticket inspecter *should* know it's valid, I never had a problem with a Luton to Blackpool ticket that way a few years back (although I realise its not quite the same thing), but if you think you might have a problem print the relevant pages of the Routeing Guide and take them with you.