Appeals process a sham, sherlock
As any fule kno, the parking operators' appeals process is a tactic to get to to engage, admit who you are, that you drove the car, you parked there, and that they have valid contact details for you.
Typical advice from Pepipoo, Money Saving Expert etc is to ignore them completely. This was successful for me a couple of years ago when I got a ticket despite having parked properly. Sequence of threatening and finally desperate letters, followed by them giving up. Not sure if introduction of POOPLA has made any difference to this, IANAL etc.
I'm not in favour of people parking where they like, but private parking co's have killed the golden goose by pursuing the money rather than acting reasonably or fairly.