Free Traffic Legal Advice

Hey Guys and Gals,
Got an awkward issue on residents parking in Cardiff.
My son lives and works in Cardiff, has a current permit holder parking for Penarth road. Often parks at the front of the house. But limited spaces. He has lived there for 2 years and the parking hasn't been changed. There are not enough spaces for all the cars and permit holders living on this section, however the council still issues 2 or more permits per property which are multi occupancy. There are a few marked parking bays which are faded. all along the road are double yellow lines which also pass through the parking bays. Residents park along here all day all night and parking is offset to the main road so no obstruction is caused by parking here. Recently he received a Cardiff County Council penalty charge notice for parking as everyone else does on a double yellow line. Not causing an obstruction but also not visibly in one of the parking bays,( think there are 3-4 supplying 12 or more properties), also with double yellow lines through them. He has never 
had a parking ticket before and all vehicles reg are uploaded to the council web site so any traffic warden could cross check.
He appealed and was rejected on the basis that he parked on a double yellow line.
Is it worth pursuing, claiming unfair enforcement of parking restrictions due to unclear and ambiguous parking bays and double yellow lines?
If he pays he still has a problem of where to park even as a permit holder!

Advice welcome
Rep

Thanks again jfollows. I might use that link instead
Rep

Hello everyone, Just received fine from Stansted today. Took 6 days to arrive lol.The photos taken show both back and front of vehicle including driver. Does this alter the appeal process or declination of providing details of the driver?

Hello guys just wanted to check if the reply to this fine is the same as the reply when forum was known as PePiPoo?
Express Drop off at Stansted is limited to 10 mins i think missed time limit by 1or 2 mins as flights were cancelled due to Iran war. Somehow payment didn't go through either. Is the reply letter the same as was previously advised when the form was known as Pepipoo? Shown below:

This is an appeal by the registered keeper - No driver details will be given. Please do not bother with your known fishing expedition in an attempt to get driver details to try and get around the fact there is no keeper liability (and never can be under POFA).

Due to this being airport land you will be well aware there is no keeper liability due to the byelaws in force and the fact this is not relevant land.

As there is no keeper liability then liability cannot flow from the driver to the keeper and thus is an auto win @ POPLA. Please therefore cancel the notice or issue a POPLA code where you will auto withdraw

If you waste your time asking for driver details this will be ignored and you will still lose at POPLA if you dont cancel the PCN

So let's save my time and yours and cancel this PCN you simply cannot win this (and you know it).

Thanking you in advance.
Rep

my son parked in a residents bay in London less than 1 hour before it expired and was free to all for the rest of the evening and all next day Sunday. Does he legally have to pay or can he ignore it. His only excuse is he had to park as he had paid for Airbnb near by, and there was no where else to park.
thanks