As I understand your narrative, you stopped and waited whilst a motorist reversed out of a space on the opposite side of the road, and you then moved across to park. Nobody boarded or alighted from your car. This is what I would call an "in traffic manoevre", and you should submit representations on that basis. There has been a recent successful case on this forum recently on this subject, but I can't remember where, sorry ! Others will more knowledgeable will hopefully soon contribute. The only downside is that councils refuse over 95% of representations, because they know most people then just pay-up, not being up-to-speed on the law. Also if you do take them to adjudication at London Tribunals it would be with the full PCN penalty in play, no discount option.