Fined by Napier for parking for 5 minutes in Totnes. What do/don't I say in my appeal?

And thank you in advance for any help.
We waited, engine running, while we consulted a map. The parking charge notice itself proves we were there for 5 mins. I think there is an agreed 'grace period' for IPC members of ten minutes.
I don't have a pic of the car park sign, but looking at other Napier signs online, they don't specify a 'free' grace period.
Are there things I should and shouldn't say in my appeal?

https://www.ftla.uk/private-parking-tickets/read-this-first-private-parking-charges-forum-guide/

You need also to understand the difference between a “consideration period” which allows you to read the signs and decide whether or not to enter into a contract, and a “grace period” which allows you extra time after paying to park before leaving.

You will need to post up the PCN for proper advice.

On the face of it, your appeal basis will be - no contract between the driver and the parking operator - you considered the terms and decided to leave well within the consideration period.