OP, let's cut to the chase so that we can focus pl.
On the day in question, there was a car parked on the opposite side of the road, leaving insufficient space for other vehicles to pass. To ensure traffic could flow safely
Then don't park there at all..would be an adjudicator's response. Forget this.
While I acknowledge the presence of footway parking markingsReally? Where would you find these in the Traffic Signs etc. Regs?
They are merely white paint, end of. Absent a regulatory sign to give (or purport to give) these markings legal effect then they are paint without a purpose.
Parking on the footway in London is a statutory prohibition which cannot be varied by splashing paint on the road.
The signs are items 12-15 in the Part 2 table here:
https://www.legislation.gov.uk/uksi/2016/362/schedule/7/madeItem 14 is the only one which could apply and only if used varied as per Variant no. 2.
So, send a FoI request to the council, NOT parking.
I refer to the markings on the footway as can be seen in the attached GSV screenshots. I should be grateful if you would advise me as to their purpose and, if in connection with a disapplication of the London-wide statutory footway parking prohibition, the location of the nearest mandatory traffic signs which alone convey the meaning of these markings to motorists and a copy of the council resolution which authorised the parking of vehicles in this manner. For your information, s15 Greater London Council (General Powers) Act 1974 refers.
As regards your challenge, I'd simply say that you believed that parking with two wheels on the footway, as you did, was permitted at the location.