And I'm not an apologist for scumbag parking companies, I'm just trying establish where we draw the line.
Ah Mickle as you well know what is lawful is not always right and vice versa.
A company or private individual has no legal right to impose a fine, period. However until probably May this year, the law allows them put a clamp on someone like Gti's Gti, make him pay up (for up to around £140 according to case law) or they don't have to release it. Since they didn't clamp his car, although Gti has committed tort against the landowner, the latter will find it uneconomical to pursue, which probably will be unsuccessful in any case.
What hasn't been said is that the Protection of Freedoms Bill now snaking through parliament is going to ban private clamping altogether likely from May. It is a critical issue for me, e.g., with a large open front yard in a popular location where public parking is in short supply. People will have little choice but to erect barriers after May to stop people parking on their land.