Surely, I shouldn't have to pay a £80 just for making a mistake?
Unfortunately, mistakes is how TfL make millions from motorists ! It is a No Stopping contravention, so one minute is an eternity. Why didn't you read the sign
before you went to the shop ?
Difficult to suggest what to put in your reps, but if it was a commercial delivery, say that you were a busy delivery driver, and was making a delivery.