thanks to bernie and others for guidance on contesting pcns at this buslane I appealed and then waited it out for six months and they did not pursue the case. good luck to others who contest these ridiculous penalty charges

I got a ticket in Finsbury Park for parking in a resident's space. One side of the road was Pay and display, the other side was residents only. I read the signs for one side of the road and presumed that applied both sides. I purchased a ticket and dispayed it. When I got back I had a ticket - contravention code 16T "parked in a permit space without displaying a valid permit". My pay and display ticket covers the time at which the PCN was issued. There were plenty of empty spaces on the street at the time so I was not depriving any residents of a space. I know that strictly speaking this is a contravention and it's my mistake. But it seems harsh to punish an honest mistake. Do I have a case to challenge this ticket?