It reminds me of two separate incidents, over 24-hours, four years ago, when my motorcycle was ticketed - off street - by the over-zealous guardians of Westminster's parking spaces.
On both occasions, passing wardens agreed that I was in a private area and that in all likelihood, their supervisor had done it but as they pointed out, it was my word against theirs and none of them was prepared to give me their badge number as a witness.
They hadn't bargained on everything being recorded on a digital camera. I was determined not to let Westminster Council get away with this and it took six months and multiple letters before they gave-up trying to collect the by now inflated penalty fines and announced they had lost the records. No apology or acknowledgement that they were working outside the law and that at least one of their traffic wardens was out of control. Mind you, there have been lots of documentaries on the same subject, Westminster and Camden being among the worst.
I rarely even bother to take my motocycle to London anymore these days. With few designated parking bays and a zillion scooters taking-up all the room, it's hardly worth the risk.