All of that is fine for bringing a civil case. There is absolutely no reason for a minor disagreement about whether a ticket was shown or not to be anything other than a simple civil dispute.
We only have one side of the situation. What isn't in dispute is that the OP couldn't show a valid ticket for travel when asked by a TOC's representative. It may have been because of something not directly under his control but just like driving a car with faulty headlights/wipers etc., the fact that a fairly simple rule has been broken is not in doubt. You suggested a that we cannot have a practice of companies who "judge on a whim whether to prosecute people". I would agree with that, hence my last post, but the OP's position is not one of those given the original clear breach of the rules of the NRCoT regarding presenting a valid authority to travel. Any official wriggle room would clearly allow such unfair judging on a whim which i would be against. Unauthorised 'letting people off' by frontline staff is not really the essence of this thread.