Firstly, thank you for your prompt response. I wasn't expecting such a fast reply!
I've uploaded the front of the letter. Someone went to the car park at the weekend and took a photo of it stating 45 mins max stay but I don't know how to find out when exactly this changed.
Actually, this is from the dashcam footage of the vehicle on the day:
https://imgur.com/a/B4dpNYy.
It looks a lot similar to the sign in Google Maps stating 2 hours, than the photo of the sign taken at the weekend, which shows the sign facing the inside of the carpark which would be impossible to see when driving in:
https://imgur.com/a/Eepj6vt.
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