An H&A Print car parked at Majestic Square was tipped over on Wednesday night by a group of "young lads", owner Ed Boyd says.
It is the fourth time in six weeks one of Mr Boyd's cars have been tipped.
Footage from CCTV cameras showed the group pushing the car over, though Mr Boyd was unsure of how many were involved.
He said the car was being used for advertising. He was called about 9.30pm on Wednesday, but the car had been picked up by the time he arrived.
There was some damage to the right side of the vehicle.