What a pity you had not discovered this site before you blundered into their trap. In future, the keeper must not, ever, ever, ever, EVER, identify the driver. There is no legal obligation to do so to an unregulated private parking company.
All you had to do in your initial appeal was tell VCS to go rotate on a sharp stick as the land is under statutory control which means that they cannot hold the known keeper liable for the unknown drivers alleged breach of contract.
There is no “fine” or “penalty” because no “offence” has been committed and VCS are no “authority” of any kind. They are simply a private company of ex clamper thugs. However, the known keeper has identified the unknown driver who is now known.
Your appeal to the IAS is a wasted effort. They are not going to uphold your appeal. You have identified as the driver and they will hold you liable.
The only way you are going to resolve this is at the ultimate dispute resolution service… the small claims track at the county court where the only truly independent arbiter, a judge, will decide whether you owe VCS a debt.
For now, show us on a Google map satellite view EXACTLY where the vehicle was stopped. There is a slight possibility that the location is outside of VCSs area of control. Please show us the NtK that was received. We will try and pick through it for any technical failures but having identified the driver is the equivalent of of shooting your self in both feet.