When you came back to the car did you take a picture of where you were parked showing the double ;ines and your blue badge displayed.
I had a PCN when on holiday for parking on what I thought were double yellow lines, but when the PCN came through it stated I parked where no parking was permitted with the double yellow lines at right angles on the pavement. My photo showed they wern’t visable where I parked so got the PCN cancelled.