Thanks. That page has lots of links on it. The one marked “Challenge a PCN” leads to where I went before, with no ability to add to a previous challenge.
However, if you click on “Contact red routes” then “Online form: ask a question” and then “Make an enquiry”, you can choose “Penalty charges and enforcement” to post up to 3,000 characters and upload docs. Just giving all this detail as it might help other people.
I will upload your text, appropriately adjusted, and and will post anything that I get back.
You text includes the statement “The alleged contravention did not occur”. I think that I could add “because the vehicle was crossing the bus lane to reach an off-street parking place.”
And then “In any case, the PCN is unenforceable because … …”