I believe it is. And you are right. TrainSplit
does allow you to specify an itinerary with a change of trains, but
not with the Anytime Day Single £6.40 ticket.
Have you obtained an itinerary from TrainSplit for the via St Pancras to Stratford Intl. via Ramsgate, which allows you to change trains or break journey at Ramsgate (or anywhere else)?
Insert a change (at Ramsgate) to require a change/wait, and even if
both connecting services are direct from St Pancras to Stratford Intl., the total fare is e.g. £65.40. (2 x Super Off-Peak Single tickets, St Pancras-Ramsgate and Ramsgate-Stratford). Does TrainSplit fail to implement NRCoT correctly?
Accredited journey planners have to implement the Routeing Guide and the NRCoT in accordance with industry standards. That means that there are some cases where you will not get a journey planner to give you an itinerary despite the itinerary you want following a permitted route.
For example, there are numerous fares for which the mapped routes give LONDON as an option (i.e. travel is permitted via London, usually across it), and yet which do not include the usual marker of cross-London validity, a Maltese cross. The Routeing Guide is clear that in this scenario, a cross-London transfer is permitted in the same way it would be if a Maltese cross did exist. Yet booking engines are not permitted to suggest a cross-London transfer for such tickets (other than a walk for very short transfers, or a make-your-own-way transfer for overnight transfers where the data gives the Underground etc. as being "shut").
This situation is, I imagine, similar. The internal industry accreditation rules and guidelines ban booking engines from offering itineraries that involve a change, if they can only be justified as a permitted route by virtue of the direct trains rule.
So what I am saying is that, whilst TrainSplit et al are compliant with the industry rules and regulations (well, TrainSplit is, but some other providers are not!), that does not mean that an itinerary they are unable to provide is automatically invalid. One must consider the contractual rights granted to the passenger in order to determine the validity of any given itinerary.
I also struggle to see how anyone can say that break of journey (at least in the context of stopping "short") is not permitted for a Southeastern circular STP-SFA itinerary, given that all compliant booking sites will state the break of journey conditions applying to that ticket: namely that break of journey is permitted!
Again, unless that is qualified then I cannot see how anyone can argue that it is not permitted when the passenger is explicitly told about (aka granted) that right when booking. Otherwise the TOC is trying to retrospectively change the conditions on which the ticket was sold, which they cannot do! I suspect it is another case of the NRCoT and ticket conditions needing to be clarified, if the TOCs are not happy with the current legal position.
I can see that the right to resume the journey once broken is somewhat more conscientious, but the right to initially break it is so clearly granted that is strikes me as incongruous that anyone would suggest you cannot do that!
(Of course, I am aware of the practical implications, but I am talking from a legal perspective here
)