Here's another rant linked with illicit fines.
About a year ago I went to the weekly discussion group I did with international students. I could find nwhere to park so I parked in the local Lidl, where there is free parking for 2 hours. I got back after 2 hours ans 6 minute and drove away. A few days later, OH had a letter fining him £60 for the 6 minutes - I was using his car. I wrote a letter explaining what I had been oding and asking for leniency, but thought I'd check on whether the fine was legitimate. On the Martin Lewis website 'Money Saving Expert' I discovered that the private firm employed by Lidl had no legal right to impose fines, since it was not the police. The site advised simply ignoring the letter and said that I would receive more demands and then phone calls, but if I ignored them all the demands would eventually cease. Sure enough, the demands got more and more insistent and fines were imposed on fines because I had not paid. Then the phone calls began, but the caller always asked for my husband and as it happened, he was always out. The fine was reduced tby stages to the original £60 again. Still we did not reply or pay. It is now some months since we heard anything and we have never paid, though we were threatened with debt collectors and court.
I thought it worth pointing out that these firms have no right to impose fines and that the most they can do is make a reasonable charge for the extra time that the car occupied the space.