PCN code 57: parked in contravention of a bus ban
What this contravention code means, and how to appeal it · On-Street
Code 57 means the council or TfL recorded your vehicle as parked in contravention of a bus ban. A valid permit or payment that simply didn't show, or signage that wasn't clear at the time, is a real basis to challenge this rather than pay it.
Full description on the ticket: “Parked in contravention of a bus ban.”
Can I appeal this?
Yes. This is a statutory Penalty Charge Notice from a council or TfL, not a private charge, so you have a formal right to challenge it before it escalates into a Charge Certificate.