Free Traffic Legal Advice

I'm really sorry but I've had a very difficult week and just couldn't spend any time on this so I paid it to get it out of the way. Thank you for the willingness to help and I'm sorry that I wasn't able to take up your kind offers of assistance on this occasion.

Yesterday I parked for a few minutes in a residents' parking bay in RBKC. I entered the road the bay was in at one end, where I noticed a parking attendant, and parked towards the other end, at the end of a fairly long bay. Opposite the bay where I parked, on the other side of the narrow street, was another bay which had two suspension signs, affixed to a hoarding. As the council often put more than one suspension sign up for any particular suspension I checked it but it related to the bay opposite where I was parked. Very close to where I parked, and on the same side of the road, but in a bay separated by mine by a few feet, there was a post with the residents' parking notification sign but no suspension sign. 

I left the vehicle and went around the corner to a shop and returned after 5 or 6 minutes to find I had a PCN. I was surprised as I hadn't seen any suspension signs for this bay but on looking more closely I saw that there was a post much further down the road that I had driven past before parking but there was a large and tall van parked right next to it, which totally obscured the suspension sign if you were driving past and largely or totally obscured it when on foot.

As I could have parked in other places and had seen a parking attendant I certainly should not have parked in the suspended bay had I seen the sign. I probably don't have any grounds for challenging this but before I paid I thought I would check with the experts on here. Thanks in advance for any advice - even if it's that I have to pay.