Not sure whether I should just pay up, but as a point of principle this has made me bloody angry but I don't want the emotional circumstances to get in the way of whether it's valid grounds for contesting it.
It was my gran's funeral on Tuesday, and two days before her DH of 63 years, fell and broke his ankle. He was taken into hospital and because of the severity of the break, he was sadly unable to attend the funeral. 
I took some photos of the coffin and the flowers and went to visit him in the hospital after the service with my aunt.
I got to the hospital at visiting times 2.30 - 4 pm to find no parking spaces left despite circling the various car parks a couple of times. There is a car park at the foot of the hospital which I also tried with no success. By this time there was a line of cars parked up on the kerb by the roadside so put my car there too. It was only the next day when I noticed that I got the ticket as it was quite dark by the time I left just after 4.
This was genuinely one of the few areas left at the hospital - there are residential streets nearby but these are signed rightly so saying residents only.
It was a sad enough day as it was, but that ticket has just made me so angry, someone cashing in on peoples misery by issuing tickets at a hospital with woefully inadequate parking. I wasn't aware of any signs nearby saying parking forbidden, the kerb was a wide one by the roadside (used by ambulances, so a no no for parking on anyway) far away from pedestrian use who would use a much more convenient route to access the hospital.
I am going back to visit him this afternoon and will lookout for signage there. I see on my parking ticket I can request a court hearing but just wondering if it's worth going to that bother.
Thanks for your help.