Richmond, code 12 parked in residents parking place, Kendrey GDNS, Twickenham (CPZ WR)

Hello,
I'm hoping someone can advise me, should I just pay the £55 or should I do an informal appeal?
I got a ticket yesterday:

Richmond (London Borough of Richmond Upon Thames)
12 – Parking in a residents’ or shared use parking place or zone without a valid virtual permit or clearly displaying a valid physical permit or voucher.

I had displayed 2 parking tickets a morning and an afternoon one as I was visting a friend who is in poor health and helping with a bad leak in the house.
I however did not scratch the month of the afternoon ticket (I did on the first ticket but forgot on the second)
I've attached the PCN attached to my car and a photo of the evidence.

Do I have any way of appealing this as a "I'm a visitor and I made a mistake and you can clearly see I was displaying 2 tickets and make a mistake" or do I just suck it up and pay it?
PCN:


Evidence from the website:


Thanks so much!

I would make a polite ask saying you presume the PCN is for not scratching the month off on the afternoon permit and you simply missed doing it. 

And scratch the month off the permit and take a picture of it to show it can't be reused, noting the serial number as per the council's picture.

 

I think that is a really good idea, Thanks!