I agree, Eddie, but I don't know about a precedent - so many factors are involved (length of overstay, pressure for places to park) that I don't think the court will produce anything like a guide to how much is extortionate and how much is fair. So it could all happen again and again with different results. The judges so far have obviously thought £85 is a mere bagatelle; I would have thought £30 or so would be easily enough to constitute a deterrent. It's not as if the company has to tow the car away or anything, they just splash tickets around, it doesn't cost them anything.
Good luck to him, say I.