only entered last 3 letters of registration need help with legal appeal

On a separate point, can I commend the ICO Code of Conduct for surveillance. Some interesting points arise from use of Automated Number Plate Recognition (ANPR) - see section 7.1. and in particular this:

When storing the information and cross referencing it with other
databases to identify individuals, you will need to ensure that these
databases are kept up-to-date and accurate and are of sufficient quality
to prevent mismatches

So if the camera takes your personal data (registration) and stores it to then cross reference with the registrations inputted, might it be argued that

(i) an accurate, quality system would be able to marry up the 3 letters that were inputted?
(ii) that to require more than 3 letters was, in any event, to process more personal data than reasonably required to check for payment

I suspect that they would struggle to prove that at the same time as the parking event there were multiple vehicles with the same 3 last letters.

Happy to see if I can draft something bespoke for this. It's frankly bonkers for them to pursue it. There is no loss.

I can't do anything without sight of the letter of claim. Can you:

(a) take a good quality photo of it (having first covered up your address and car reg);
(b) download Dropbox to your phone/PC;
(C) save the photo to Dropbox;
(D) put the link on the forum changing the http:/ part to hxxp:/

I think that covers all the steps. A fiddle, yes, but necessary. I think there's enough detail in the posts/ news articles that we understand the background well enough.