Free Traffic Legal Advice

After entering a car park and finding a bay, the driver exited the vehicle to pay for parking. There was no online option or ticket machine but a sign that said for parking please go to the white hut on west quay road. They walked up and down this road to find no obvious white hut to register for parking. After getting the family back in the vehicle they left the car park. They then received the private car parking letters threatening bailiffs etc and now have a HMCTS claim form. The driver no longer owns the vehicle the claim is against but did at the time of the offense.

I will attach a picture of the claim form. https://www.imagebam.com/view/ME1AW1IR

Thank you in advance.