A two part challenge. Was your sister with you?
----------
I am challenging the PCN on the grounds that the contravention did not occur and that in any case I did fulfil your requirements at this location. I have two points.
1. I took out a RingGo session for the free hour at 14:04. It took me a few minutes to do so as I had to download the RingGo app, register, and start the session for the location, and I did not leave the vicinity of the car. This was a reasonable time to perform this task as it is the method you ask us to use when parking.
2. The contravention of not paying to park did not occur anyway as you cannot pay for something that is free. I only stopped briefly to buy coffee and was well within the free hour.
I enclose the receipts for the parking session and coffee and look forward to your early confirmation of cancellation.