Just got a PCN for parking on an almost non-existing double yellow line last week in Leeds, around the University where I work. It was raining, gloomy and wet and I managed to park one wheel on shoddy double yellow lines which were hardly visible and I don't believe to have had T bars at the end.
I didn't know what I was given the ticket for at first because the cause was "01: Parked in a restricted street during prescribed hours." and I looked around and saw no signs of any parking restrictions. I took pictures of where my car was with a digital camera just in case.