Tent camping at B On Tweed Seaview CC site

Does anyone know why frame tents over 3 1/2 feet high are not allowed at the above site? Berwick on Tweed They would have a sea view but are not permitted as they would stick up above the wall where they are pitched. Obviously the caravans and MH are way above this. A freind of mine went this summer with his wife & six children after booking He travelled all the way from Plymouth and was turned away. It was going to be his first holiday in six years as he has been out of work for the last ten years. He only has a secondhand medium sized frame tent. He went home disgusted!! All he wanted was a holiday with a sea view