So how much before your train is reasonable?
By your interpretations there is nothing stopping someone turning up at the station 2 hours early knowing their train is already delayed at the other end of its journey and jumping on the next available train 2 hours earlier. I don’t agree with that interpretation.
You may disagree, but that's what the PRO requires in the event of anticipated delays of 61+ minutes, and what the industry has chosen to adopt as its terms and conditions. We have provided examples which demonstrate why any other interpretation is clearly unsustainable.
Being able to take the next available train in the hypothetical situation you describe doesn't seem outlandish, particularly so if the frequency of services is hourly or even less. For instance, imagine you're travelling on the Far North Line, where there are only four end to end services a day. If one train is anticipated to be delayed, meaning you'd miss your planned connection/appointment etc. it would be entirely reasonable to be able to take the previous one, even if that's 3 hours earlier.
But clearly that is a very niche situation - most people will not turn up to the station that early, or be able to change their plans on the day to that degree. Far more people will be in the situation of being at the station in time for an earlier, delayed train, which is would be unreasonable to bar people from taking. For one thing, why should the railway avoidably increase its Delay Repay liability?