When are you travelling? It should be possible to obtain an itinerary (feel free to PM me if you don't want to reveal it in the forum).
NRCoC 13(d)(i) states "The use of some tickets may be restricted to trains which take routes passing through... particular locations... These restrictions will be shown on the ticket."
In this case, there are tickets that are restricted to trains which take routes passing through High Wycombe, and this is stated on the ticket.
As long as the train passes through High Wycombe, that condition is satisfied.
Virgin Trains TMs are fully trained on this and ensure that you will be relaxed and enjoy travelling with Virgin Trains. They all have a forward-thinking approach and
full training is provided. They all posses fantastic customer service skills and give brilliant customer service. (
source)
In fact the training is second to none (
source), so obviously includes knowledge of 13(d)(i) so you have nothing to worry about. Relax!