I don't disbelieve the OP either, but am not as confident as you are for the simple reason that the TOC proceeded with a prosecution despite the OP saying at the time that he had boarded at Mossley and confirming it again in writing later. Without knowing what evidence the TOC considered before deciding that a prosecution was warranted, and without also knowing what evidence was presented in court, I say that it isn't possible to say with any certainty what the likely outcome of a rerun of the prosecution would be.
That would be evidence of journeys made on other days, which is of exactly zero relevance to the journey made on the day in question. To argue from absurdity: showing evidence of all the days that I didn't kill people isn't a suitable defence of a murder charge.
I agree that evidence relating to other journeys is very weak evidence indeed and wholly circumstantial in relation to *this* prosecution, for *this* journey, but it is not vastly more so than the evidence that the TOC *presumably* has that the OP did not board at Mossley, in the form of the *presumed* witness statement from a Manchester-based RPI who did not see the OP board.
I acknowledge that it is of course *possible* that the TOC has other evidence against the OP, and indeed *possible* that the OP is either lying or mistaken.
It is also difficult to give a precise estimate of the OP's prospects of success without seeing all the evidence available to each party, which is clearly not realistic. My estimate of the prospect of success with a defence for the byelaw 18 charge following a SD was based on the following two assumptions, which may not be correct for all I know:
1) the OP genuinely boarded at Mossley,
2) Mossley had no purchase facilities at the time the OP boarded the train;
3) the OP truthfully stated this to the RPI at the first opportunity, and;
4) the OP genuinely did not receive the summons
If any of the assumptions I have made are erroneous, for whatever reason, then clearly the value of my advice, being based on false assumptions, would be gravely and profoundly reduced. In particular, it is conceivable to my mind that Northern might be able to produce evidence that Mossley did have ticket purchase facilities at the time the OP boarded, in which case there is likely little worth in making a SD.
However, if my assumptions are indeed correct, and the OP should know whether this is the case, then one presumes that the TOC won't have any additional evidence besides the circumstantial evidence of the RPI's witness statement, which, in my view, would not be sufficient to prove the byelaw 18 charge beyond reasonable doubt when faced with a defendant whose sworn evidence to the contrary has presumably survived cross-examination. If so, then the OP was wise to refuse to sign the RPI's mistaken account of events.
However, in general terms, I think members of this forum should start from the presumption that an OP is telling the truth unless there are glaring absurdities or inconsistencies in their account, and try to follow this line myself. I happen to believe that this OP is truthful, which has not always been the case in relation to some other nameless OPs I have seen in this section. If we collectively start from the assumption that all OPs are lying, then honest posters will be driven away, and the quality of the advice will suffer.
In relation to the byelaw 23 offence, we have not received enough information to be certain whether an offence occurred. If the RPI asked simultaneously for name, address, and lots of superfluous information (e.g. date of birth, telephone number, NI number), then it seems probable that anything other than immediately giving his/ her name and address is technically a breach, however understandable and reasonable the OP's actions, if he/ she is to be believed, in querying the need for the superfluous information. The BTP officer may or may not be able to provide evidence of some sort on this point.
That said, even if the byelaw 23 offence is proven, it would still be worthwhile having made the SD if the byelaw 18 offence is found not proven. I suspect that there is a good chance that a sympathetic bench who have just acquitted on the byelaw 18 offence would impose a much lower fine, or even a discharge and no fine at all, with minimal costs.
Whilst the OP cannot know with absolute certainty what evidence was submitted to the original hearing, I agree with FareCop's helpful advice, that, if, as I believe, he/ she is being truthful, the best course of action at present is to make a SD. Edit- as MikeWh points out, the OP did receive the initial correspondence from Northern, but not the actual summons, but receiving correspondence other than the actual summons does not affect the validity of the SD.
Even if the chances of success with a defence are truly as low as DaveNewcastle makes out, resetting the matter to summons by making a SD would still at least give an opportunity to seek a out-of-court settlement with Northern.