LB - Ignore the ticket and any further correspondence that arrives. The only thing you need to respond to is a letter from your local court ifone arrives which I doubt will happen. In the meantime take a photo of the carpark and the sight. If it does go to court you will have some evidence to take with you.
Whatever you do, or DON'T do as the case may be is enter into any dialogue whatsoever with this company. Even if people come to your door. Tell them to f*ck off. Do not let them into the house.
There is no way they will pursue this, but in the meantime they will send all sorts of threats promising plagues and all sorts....