I would have recommended paying the fare due (and not anything more) but...
I called National Rail Enquiries - told them the details of both my tickets and the journey and they told me over the phone that my journey and tickets were valid. And so they put me through to the GWR customer services team over the phone, who also took all my ticket and journey details and also told me it was valid and apologised.
If you recorded this call or can obtain a copy of it, or get this in writing, I'd not make an offer to pay at this stage. But I wouldn't say I was refusing to pay; I would be stating the facts.
They told me I could appeal if i did receive a fine.
But them the ''Pre-Court Settlement Offer'' comes in the post, demanding payment in 21 days or face prosecution, criminal record and additional fines - with no mention of any right to appeal or dispute.
There is confusion here; I think they meant you could appeal if you were issued a
penalty fare. But this did not happen. A
fine cannot be appealed but a fine cannot be issued unless you are found guilty in court.
I think what I am most offended by, is, I am clearly not a criminal or fair avoider, I made every effort to buy a valid ticket and thought I was in possession of one. So why would GWR's first response be to try and prosecute and fine me and not offer for me just to pay the excess fare in this case where both their staff and my own possible misunderstanding was to blame.
I recommend putting this to one side for now, and deal with the facts. Once it's over, then deal with the poor customer service element. I don't want to go off topic here, so I won't say what I want to say about GWR and what I think of them, as it won't help right now.
I would write to GWR; feel free to ask us to proof read your letter before sending it. Keep the letter concise.
It may also be worth contacting the Rail Ombudsman:
https://www.railombudsman.org/
If it does go to court, I'd recommend Penman Sedgwick (
http://www.penmansedgwick.com/PracticeAreas/Criminal/FareEvasion.aspx ); many of the example cases were forum members and some examples were posted on this forum. I'd fully expect a victory in a case like this. But do not attempt to represent yourself.