I believe I'm correct in saying that private companies don't have any authority to fine/clamp/tow etc in the way that councils do?
The can't do any of those, but then councils can't fine you either.
The charges for an alleged breach of contract can most certainly be enforced (if valid).
Is yours couched as a Parking Charge Notice under civil (contract) law or Penalty Charge notice under railway bylaws?
Please provide a scan of ALL of the notice with just your details and reg number redacted.
