+1
Sorry to have to say it, but I don't see a win here at London Tribunals. As we all know, the councils never give way on these, so it's the only unbiased place for a decision either way. For me, the car stopped due to the presence of stationary vehicles, so the contravention is made out.
Of course the OP has the absolute right in law to take the council to London Tribunals but the full PCN penalty will be in play, and this is definitely not a slam-dunk win, I'm afraid