"Parking"

I am a disabled driver, and not been to Barnet Hospital for about forty years until October 2014, I placed my disabled badge in the window of my car, and did not read any of the notices which were apparently placed around the car park area, as I was more concerned with getting into the Hospital for treatment. A few days later I get a picture and a penalty notice from Private Eye saying I was parked for two hours, the picture is obviously a photo taken on entry/exit to the area, but of course it is not clear enough to show whether there is a Disabled badge or not. Barnet Council allow disabled drivers up to three hours to park anywhere without penalty, and this should surely apply to the Hospital ground which after all is actually owned by the public surely. I realise that there is a lot of work done in keeping the area clean and tidy suitable for parking, but people do not go to the Hospital generaly of their own choosing. A person could be kept in overnight so what happens then do they get two £100 fines or more depending how long they are kept in?