There is no single railway-accepted definition of "journey" regardless of what the NRCOC may say . . . .
Regrettably, this is absolutely correct. The term 'journey' is effectively undefined.
What references there are, which might give some comfort to anyone in need of clarity, can be contrasted with other references which will cast doubt over them.
Sadly, no one on this forum, whether employed in the industry or an enthusiastic commentator, can remove this uncertainty. Anyone seeking clarification should avoid the temptation to be persuaded by the opinion of those who also want to believe that their interpretation is the truth. But it remains a clarification which I, and probably all the other commentators on here, would welcome.
For what it's worth, my own view is that if, and only if, the two tickets were bought in the one transaction, and if the point to point travel indicated on each ticket can be combined to form a single and continuous journey (excepting only changes that are necessary to complete that single and continuous journey), and that all the trains used for travel are operated by DfT franchised operators, and that the passenger is travelling on all of that single and continuous journey, and that they are doing so without any unnecessary breaks, then, the two tickets can be said to jointly confirm that a single contract has been formed.
If I am right, then the scope for uncertainty is vastly diminished.
[And for the avoidance of doubt, I am NOT implying that any of these factors are, in themselves, determinant of the definition of 'journey'].
But that is just my view, and it has not been tested in law. Against me is the Judgement by Hawkins J in 1979 in
GWR v Pocock where he explicity declared that when the passenger arrived at the destination printed on the ticket that "the contract was at an end".
I'm not aware that any of the other points of view have been confirmed in law, (though it would be very helpful to passengers if they have been, and I'd be grateful to learn from those decisions).
NRE is the "definitive source of info for all passenger rail services on the National Rail network in England, Wales and Scotland" apparently.
It certainly does make that claim!
And I still struggle to understand what that claim is telling passengers. It strongly suggests that there are, or may be, other sources which are not definitive. Perhaps even other sources which purport to be definitive., but which NRE wants to dismiss on some unknown grounds or other. We could guess what these other sources may be . . . . perhaps prior industry documents, perhaps internet fora such as this, perhaps independent travel companies, perhaps ticket retaillers (whether approved by RSP or not), perhaps franchised operator's retail divisions. It's very hard to understand how NRE can declare itself to be definitive while operating under, either, the law of England and Wales, or the law of Scotland, where only Parliament has the constitutional power to create law, and only the Judiciary has the authority to interpret and apply it to us citizens and Companies.