[FoxtrotGolfXray 5.0]

Sorry to say, but I don't like your chances. The argument you've put forward regarding not knowing the rules is not likely to work. It's your responsibility to know the rules, not the other way around. The fact it's not sign posted is irrelevant. Similarly, the amount of time the vehicle was parked there and the level of impact to others as a result is also irrelevant.

You've got nothing to lose by trying, but based on my past experience, I don't think you will have success. The only hope you have is that you get someone sympathetic to your friends circumstances, but finding someone like that in council by law enforcement is harder than finding a reasonably priced new rwd family sized sedan to purchase!

Good luck. And all the very best to your friend.