A council Penalty Charge Notice and a private Parking Charge Notice look identical on the windscreen and obey completely different rules: different deadlines, different appeal bodies, different consequences for ignoring them. Say which one you have and when it was issued and this works out the dates you cannot miss, whether fighting it is worth more than paying the discount, and drafts the appeal on the grounds that actually win.
Dates are counted from the date printed on the notice and are the common statutory or code-of-practice windows, not a promise about your operator: read the notice, because the notice wins. This is not legal advice. Do not ignore a council PCN — it escalates to a Charge Certificate (+50%) and then bailiffs. A private charge can only be enforced through the county court, and paying a judgment within a month keeps it off your credit record. Everything stays in your browser.