Clearly the only appeal argument is the unreadability of the sign. Trouble is GSV is not up-to-date, latest view 2022 which shows there isn't even a parking bay there in that year, although a notice on the street light pole is probably a notice that the parking is going to be restricted.
All you can really d at this stage is submit informal reps on the basis that the sign is vandalised so much that the conditions are unreadable, and there is only a single sign. Councils have a duty to keep signage maintained as part of their duties under The Local Authorities’ Traffic Orders (Procedure) (England and Wales) Regulations 1996
https://www.legislation.gov.uk/uksi/1996/2489/regulation/18Your photos of the sign shows somebody has clearly tried to wipe off the black paint and failed. CEOs are supposed to not just serve PCNs but to report signage problems, and also should not serve PCNs where the sign is vandalised, but of course they do, or they get the sack !
