Should I request video evidence first or make an informal representation?
I am assuming you drove out of Wolfe Crescent, turning left into Canada St and shortly after, drove past these signs: -
https://maps.app.goo.gl/4LJugBpJe7ovx3oR6HOwever, a look on the Southwark webpage for paying a PCN shows the signs are now brought forward so they are right on the corner as you turn left; easy to miss, so maybe that's why they altered their position to make more money, as I cannot see any reason at all why they were moved.
They mean "No Entry for motor vehicles" and there is a timeplate below giving the times when the restriction applies. These are found all over London now, and it is useless relying on satnav alone, you must look out for signs like this when off the main streets, or even when you're on them ! You drove past at 15.39 according to the PCN, well within the restricted afternoon period.
If you drove to your AirBnB along Quebec Way you would have passed this sign, which obviousl you missed
https://maps.app.goo.gl/PsjPYyNg5hcxW9zL8They have also erected warning signs just after you turn in to Quebec Way to: -
https://maps.app.goo.gl/eD4EHscQ4ZyAzXYa9These are not traffic signs as defined in the regulations.
You have the absolute right in law to submit representations against the PCN, and if rejected, take them to London Tribunals, but if you do this the full PCN penalty will be in play.
If you go here and enter your PCN Number and car reg, you will be able to see their camera evidence.
https://www.southwark.gov.uk/parking-streets-and-transport/parking/parking-tickets/pay-your-parking-ticket