The history here is the signs used to be as per the pic below and there were marked bays.
What I think has happened is they abandoned maintaining markings and changed the signage to simple extent.
This document says footway parking in Elers Road is subject to a 'Formal scheme with signs and lines'.
https://modgov.hillingdon.gov.uk/documents/s64484/SCOPING%20REPORT%20-%20A%20REVIEW%20OF%20SUSPENDED%20PARKING%20ZONES%20IN%20HILLINGDON.pdfThere are two adjudications, both refused - simple one posted below. Note the adjudicator has said 'supported by a Council resolution' but I wonder if this countermands the signage along the entire road, and given that markings have gone.

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Case reference 2250371661
Appellant Roy Sawney
Authority London Borough of Hillingdon
VRM R10JJS
PCN Details
PCN HN21702689
Contravention date 10 Apr 2025
Contravention time 12:57:00
Contravention location Elers Road
Penalty amount GBP 140.00
Contravention Footway parking
Referral date -
Decision Date 08 Apr 2026
Adjudicator Edward Houghton
Appeal decision Appeal refused
Direction Full penalty charge notice amount stated to be paid within 28 days.
Reasons The Appellant did not attend the adjourned hearing.
The Appellant’s case is essentially that the signage indicating the Area where the Council had exercised its powers to allow footway parking was unclearly signed. I am unable to agree. The small blue signs (prescribed by Regulations and
supported by a Council resolution) are positioned in accordance with recommendations of the Traffic Signs Manual Chapter 3 in that the sign showing footway parking to be permitted is mounted facing oncoming traffic; and in a similar way, for example, to a speed limit sign, applies to the area beyond the sign not in front of it. The line of vehicles parked on the footway beyond that sign might have given the Appellant a clue as to its meaning if he was in any doubt. The sign with the red line through it indicating the end of the exempted area likewise applies to the area beyond the sign not to the area facing it.
This method of signing exempted areas is widely applied throughout London. I note that the Appellant has produced a photograph of what he describes as correct signage. This is in fact a very unusual (based on 30 year’s experience) example of incorrect use of the signs.
As a result of what was no more than a misunderstanding on the Appellant’s part the vehicle was not parked within the exempted area and was therefore in contravention. It cannot be said the PCN was issued anything other than lawfully.