Contesting a parking fine

I keep getting hit with parking fines and it is rinsing my finances. It makes my blood boil. I have a university education, am fully literate, speak 3 languages fluently and my IQ is above average. I still cannot understand parking signs.

Below is my latest contestation of a fine I got picking up wood preserver, sent to TFL in an attempt to avoid a fine of £80. It is relatively poorly written because I have limited hours in the day (like everyone else) and they don't deserve poetry:

'I needed to go to B&Q to pick up 5L of wood preserver. I cannot carry it so I have to drive in my car. I spend at least 20 minutes looking for a parking spot near the B&Q in Camden and am unsuccessful. Any parking spot near B&Q is either 'Resident Permits Only' or some other prohibitive signage. I try Albert Street but there are no free spots (and it's also quite far away, making carrying the heavy liquid difficult). I then try Plender street and the spot that it is legal to park in is even further away from the B&Q and unfortunately there are no spots. I continue driving and because of the road works going on in Camden, time and distance is added to my already exhausting quest for a parking spot. I drive down Camden High Street, scanning the signs to see if I can possibly park somewhere. In front of B&Q there is a van parked an the back doors are open so I can see they are loading/unloading. I read the parking sign and it says 'loading only. 20 minutes maximum.' There is also a part that states something about '4pm'. It is a busy highstreet with a lot going on, I have had a long day, spent 20 minutes (easily) searching for a parking spot. My ability to interpret a parking sign correctly is compromised considerably from the above circumstance (most of which are out of my control). Given that there are other vans parking and loading in the same spot that I have parked and given that I can see no logical explanation to interpret the cryptic signage connecting to '4pm' (I can't presently recall verbatim what the sign said), much to my chagrin, I don't interpret it as a cut-off. At that moment, given the circumstances, I proceed to purchase my heavy tin of preserver leaving my car in the loading only lane. To me, it seems within the boundaries of reason to excuse the PCN and it would be vastly appreciated. The amount being charged is a considerable amount and in my financial circumstances the fine is non-commensurate to the perceived violation. Thank you for your time. Sam'

I will probably get some humourless response and have to pay £80 nonetheless. Down another 80 squids and the efforts of a fun email.

So far, the costs of parking and PCNs that have gone to the little men in grey suits is £275.68 out of a total of £1,299.79. That is 21.2% of the total.