Free Traffic Legal Advice

I was travelling South on North Street Barking and turned left into East Street which immediately became a pedestrian zone (there were no signs to not turn left).  I realised what I had done and turned around, but I turned around just past the signs (about 20m) therefore I entered the pedestrian zone.  There was a lorry parked immediately on the right hence I had to go slightly into the zone to turn around safely.

I appealed the case but they said it is not possible to undo a contravention once committed and this contravention is complete once the vehicle passes the signs.

I would like to get peoples opinions on if I have grounds for appeal.  It would have been unsafe for me to immediately stop at the signs so yes I did move into the pedestrian zone, but purely to turn around safely and leave immediately.  There was no notification it was a pedestrian zone prior to the end of the road.

Below is a link to the following documents
Both sides of PCN (I don't have copy of what I said but it was along the lines of above)
Copy of the rejection letter
All images used on the PCN
Video from the PCN

https://www.dropbox.com/scl/fo/kc6o23m28ft8o0orj2tco/AFh89VK6f-sA_T8uYZGJFCU?rlkey=fkukfl0jzwbbre40yya2amri2&st=73xtvno5&dl=0

Street View link in Google Maps
https://maps.app.goo.gl/Lse6Y4DRBJxpfEH6A

Any advice would be greatly appreciated.

Thanks for the info.  I have made some changes to the original post.

Dropbox is difficult to work with