"Parking fine Trowbridge hospital"

We parked at Trowbridge and registered our car as per the receptionists instructions only to receive an aggressive letter with an £85 parking fine. On phoning the hospital to query this we were told it frequently happened and to come and pick up a letter to send back with the form. This means driving for half an hour each way to get the letter. The service at the out of hours emergency unit was great but surely something can be done to sort out this problem with parking. It is extremely upsetting to get a sudden demand for £85 particularly when the tone of the demand is so aggressive.. we now hope sending off the letter has been effective and debt collectors do not arrive!