Free Traffic Legal Advice

This is the street view, my car was in front of the red brick house with the hedge/ white low wall and the sign where the parking suspended sign was attached is behind the small black lexus shown in the view:
https://maps.app.goo.gl/TosnCnCZQaPRFTMX7

I received a PCN on Friday 11/7 at 08:02 for parking in a suspended bay.
I think we had been parked there for a couple of days (Tuesday pm at the earliest) and do not recall any sign. The Lambeth website states that they will put up warning notices "approx 3 days in advance" however they are notorious for putting them up last minute and then immediately ticketing.
Is there a way to check when the notice was put up and is there any national standard for the required notice period as "aim to give 3 days notice" seems deliberately vague.

Suspension sign:
https://drive.google.com/file/d/1e8ZFltPHBod9Pt7X83kmkuNeGFtKHbeT/view?usp=sharing

Photo of notice:
https://drive.google.com/file/d/12XTXOAseffmWpZyGnwMNS68NO2o3D4p3/view?usp=sharing

Our PCN:
https://drive.google.com/file/d/1nDT3-PmnXb3udI7-KkVm8srnuQPHMAqC/view?usp=sharing

The car was parked opposite the house and 2 doors to the right (terraced houses), the sign was opposite and 4 doors to the right. Given the heat on Wednesday and Thursday last week (highs of around 30 degrees in London) so we didn't do much except commute to work and did not spot the sign on our daily routine.
One reason why we had not spotted the sign is that there is a huge Lambeth planted and maintained tree right outside our house that is currently in full bloom and needs trimming to be able to see across the street and to walk under, this tree is to the right of our gate and requires crouching to walk under (otherwise you get debris/ spiders etc in your hair and scratch your face) hence we choose to walk to the left away from the direction of the tree/ car/ signage. We should be able to see the sign from immediately outside our house however this tree totally obscures the view in that direction. Could this be used as a reason?

This is our view as we walk out of our house and look towards the car/ signage:
https://drive.google.com/file/d/1_O_jppNZj_dlj0dAy29IzMy5_bpMmgZm/view?usp=sharing

The red circle is where I would be able to clearly see the sign if the tree were not there/ better maintained:
https://drive.google.com/file/d/1HmurOmeMAWIzamWFCGlEGT3Pv-aajL6U/view?usp=sharing

Where I can actually see the sign if I crouch down to the height of my 6 year old:
https://drive.google.com/file/d/1HYJO_eBRY1EGPau3m6yLNFdiHuUVGTRT/view?usp=sharing

This shows how low this tree is:
https://drive.google.com/file/d/1geJ7_6NDEjtlkj1ZeHMOT0pBl05rrDx5/view?usp=sharing

Any bright ideas?