Apologies - I have amended the subject line and attached the fine letter.
I would have paid the fine before I entered or even had I known, but as mentioned, didnt realise there was anything to be pay until this morning.
Thanks
The £15 is the daily Congestion Charge, it is not a fine.
The scheme has been running now for over 10 years so the likelihood of you getting it cancelled is low, unless there is a clever "technical" appeal. Somebody may suggest something, but don't miss the deadline on the PCN waiting for something to turn up.
It may well be worth submitting some reps on the basis that you live <nnn? miles away from London and didn't know about the scheme, and promise the offence will not occur again. After all, would a crofter living in the Outer Hebrides visiting an old friend in London know about it? You never know, you might get lucky...