This is dispute resolution, not Rumple of the Bailey! There is nothing criminal about a civil contractual dispute.
However, in civil cases like parking disputes, courts can draw adverse inferences from a party’s behaviour or omissions, but it’s not quite the same as the criminal caution about harming your defence by staying silent. There’s no formal warning like that in civil law, but if you fail to raise a key point early on—especially if it’s something you later try to rely on—the judge may give it less weight or even infer that it wasn’t a genuine issue at the time.
That said, your appeal clearly sets out your position: you are the registered keeper, not the driver, and you’ve explained why the operator cannot rely on the Protection of Freedoms Act 2012 (PoFA) to hold you liable. You’ve also made it clear that the location is not relevant land and that the parking charge is based on alleged contractual terms, not statutory bylaws. This kind of direct and early explanation significantly reduces the risk of any adverse inference being drawn later.
In short, as long as your key arguments have been made early—like you’ve done here—there’s no real concern about a court making a negative inference due to silence or delay.