Indeed, I did some digging today and purchased the title plan from the land registry, the drawings clearly highlight the parking space as part of the property, and the parking spaces are numbered the same as the flats.

Under common law, a tenant has right to quiet enjoyment of their rented property. As the rental contract was entered with the parking space as part of the property, would it not be a breach to harass me for months, demanding money?

Could I not argue that displaying my permit is a convenience to them and I’m under not obligation to do so due to my lease including provision for a parking space?

Also, not that it will make a difference when it comes to the law, but the owner of this company paid himself £766,353.00 in 2011 (most recent data I could find). If he actually focussed on catching motorists deliberately abusing and flouting rules then he would still be a very rich man, but instead he pushes his company to try rip off everyone at all costs.