The warden is operating in the pay and display Gateway car park in Trowbridge above Argos and Next. Here is the warden's photographs of the signage.
Here is a truer picture of the situation.
The actual situation is that some companies have reserved parking in the car park, but only from Monday to Friday. On the weekend their spaces are available to all motorists. The warden is ticketing motorists on the weekend and staging photographs to miss out the full parking terms and conditions.
The Prankster calls on all motorists in that car park to be wary and watch out for this and other UKPC rogue ticketing practices.
The Parking Prankster