Free Traffic Legal Advice

Afternoon folks,

Looking for some advice regards a fine issued by Horizon Parking for Tesco Extra in Colney Hatch for overstaying the time limit, please.

Trying to be brief, the driver of the vehicle went to test drive a car at a main dealership and was advised by their salesman to park in the Tesco car park next door as it was free. Long story short, for a couple of reasons the driver of the vehicle ended up staying for a protracted period in the dealership at the salesman's request. Due to this, the driver has now contacted the dealer, asking that they pay for the charge and their response is awaited.

However, in the meantime (and in the likelihood that they refuse), just wondering if there's any other legal route to dispute this charge with the PPC?

Photos of the covering letter and back and front of the PCN below:

Covering letter: https://ibb.co/xq7ZvPnt
Front of PCN: https://ibb.co/VWvDVsm5
Rear of PCN: https://ibb.co/WpNbt3cS

Many thanks in advance for any advice