I am a member of a gym which has a small car park. When you attend the gym you have to input your car reg inside the gym. I bought a new car in March and on the same day I collected it I went to the gym, inputted my car reg which as it was new the system wouldn't recognise. The attendant told me not to worry and I signed in as usual. Of course I then receive a PCN which I appealed and provided confirmation from the gym that I was a member and attending the gym at the time in question. For some reason the appeal was turned down and I have now received a demand from Civil Enforcement threatening escalation to a third part collection agent and possible proceedings. As the gym whose car park it is has confirmed I was there can CEL demand payment. What is my next step. Is there a standard letter I can send to CEL advising that they have had confirmation from the gym that I was there and signed in.