If you didn't understand the yellow sign with the "No Parking" symbol, and the hours when parking is not allowed, then you are going to get a lot more PCNs in the future. Signs like this are the whole basis for imposing parking restrictions, together with a single yellow line to alert you to a restriction existing, and the need to look for the sign to make sure you can or can't park.
CLearly you were misinformed by Ringo, and may have the basis for an appeal, but the sign is present and clear so I doubt this would succeed, but others may differ so wait a bit to see what they may say.
