The council's problem - it shouldn't be a problem, but it is - is that for contraventions which relate to orders made by them they would specify that the whole vehicle is what's in play, overhang and all.
But this isn't based in an order, it's a statutory prohibition and the wording couldn't be clearer:
1)Save as provided in subsections (3), (4), (7) and (11), any person who causes or permits any vehicle to be parked in Greater London with one or more wheels [F2on or over any part of a road] other than a carriageway [F3, or on or over a footpath,] shall be guilty of an offence
The CEO should have known better and the authority should know better than to spout what is objectively disproved by their own photos. But this is symptomatic of the poor standards which are widespread in councils.
Their pensions are good though!
The photos show a badly damaged footway which suggests that you don't have a crossover although there seems to be a sloping kerbstone in the background. Whether this might be an issue for the future, I don't know, but it's not germane to the PCN.