Your informal challenge against the PCN served to your car has received the usual Fob-Off letter.
It's very important you, and indeed all residents in the London area, understand that all London councils game the system ruthlessly to maximise the cash income from PCNs. So virtually
ALL informal reps are rejected, Why so ? Because the council know that >95% of people then cough-up to get the discount, not being "au fait" with the minutiae of the regulations and thinking they'll be risking huge sums of money if they take the matter further. Needless to say this is not true. The maximum financial exposure is the PCN penalty, and has been since the original 1991 legislation, (under a Tory government BTW). It is a very lucrative source of cash for them even if most people pay the discounted amount. Have a read here:-
https://www.whatdotheyknow.com/request/kingston_upon_thames_pcn_revenueCan you please post a GSV link to the exact location. The photos show the bay markings are considerably degraded and worn, such as to make enforcement a mere money-grubbing exercise. Councils have a duty under Regulation 18 of The Local Authorities’ Traffic Orders (Procedure) (England and Wales) Regulations 1996 to place and maintain adequate signage announcing the restriction within the Traffic Order to motorists.
https://www.legislation.gov.uk/uksi/1996/2489/regulation/18Here it appears they have failed in their duty to maintain.