It’s (not) fine

Yesterday I got a parking ticket, shock, not a speeding ticket as usual, but a fine for being stationary. What bugs me about it is that I was parked outside a friend’s, partly on the (wide) pavement so as not to obstruct traffic - I didn’t realise this was illegal, mainly because everyone does it, there are more cars than driveways/garages/parking spaces here and the roads aren’t hugely wide.
The funny thing is that the time quoted on the fine is wrong, by at least an hour...I‘m considering emailing and asking what evidence they have...