Depends really, on the face of it the driver didn't comply with terms and conditions put in place by the hospital. Lack of parking is a major issue at lots of hospitals. So unless you have other grounds for appeal like poor or inadequate signage or the PCN isnt POFA compliant (to all intents and purposes for appeals it is) you have 3 choices.
1. Start the long road to hoping they give up. You'll need to appeal which will be rejected, appeal to POPLA, which will probably be rejected. Ignore the debt collectors letters whilst keeping an eye out for the letter of claim that will need to respond to. Then you'll need to file a defence and probably attend a mediation call. Then if you're lucky the will discontinued the case, if not if you lose in court you'll be out of pocket to the tune of £300.
2. Name the driver and pass liability to them.
3. Pay it before the discount period ends.
The best option though is PALS.
