Your PCN was not issued under the London Local Authorities Act 1996, so Davy Duthieuw v London Borough of Ealing is irrelevant. I've written a revised draft for you to send:
Dear London Borough of Newham,
I am writing in response to the Penalty Charge Notice (PCN) referenced above, which was issued for an alleged contravention of failing to comply with a no entry restriction, captured by camera enforcement on 9th April 2023.
I would like to bring to your attention that at the time of the incident, I was positioned in the correct direction, and therefore, I would not have been able to observe any no entry signs that may have been present. Prior to the start of the footage I was turning left out of the road but there was an incident so the road was blocked. My son needed the toilet so I reversed on the road I was on and parked up. My vehicle never left St George's Avenue and I never could have seen the no entry signs in question, as those signs are visible to drivers on Upton Park Road, not drivers on St George's Avenue.
In light of the above the alleged contravention did not occur and the penalty charge must be cancelled.
Yours faithfully,