My wife has the exact same fine 2 days later. She also noticed that the sign is obscured by trees but also too high to actually see upon entry from the drivers side. I know Croydon Council is broke but this is daft. Adding to that even if you were to see it upon entry the cars parked up on the side makes it impossible to turn around anyway so they get you regardless! Keep us posted on your outcome and we shall do the same (although we have not paid the fine yet as we are drafting a response)