So, send a FoI request to the council, NOT parking.
Why bother, to summarise your last post!
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.
So far we seem to answer our own questions with posters putting themselves out to hunt through GSV and other sources and instead of putting the issue to the council (NOT parking) regarding what formal arrangements they have made, if any, to disapply the governing legislation you harp on about it being a Sunday etc. ..as if this makes any difference.
IMO, your feelings of injustice alone won't win, you need to take action.
But it's your choice.