In summary the person concerned received an NTP / PCN from Smart Parking. Appealed it (admitted they were driving!). Still gathering all the info - they mentioned they "were sent to a portal" - appealapcn dot com (claims to be AI powered) - did search the forum and can find no mention of them but they didn't do anything with it (don't know who sent them to this and it appears they may not have heard back about the initial appeal).
Debt recovery plus have sent them 2 letters, both for the same alleged "offence" but with different reference numbers
From reading the forum the advice would appear to be to ignore all communication unless / until a Latter of Claim arrives.
Any other advice appreciated.