Offences under Bylaw 14.3 can only be committed by the "person in charge of the vehicle" (i.e. the driver who parked the car).
The TOC does not know who the driver was and has no way of finding out. Bylaw 14.4 may extend, to the owner, a liability to pay a penalty. Whether it would extend to form the basis of a criminal prosecution I don’t know. But once again, the TOC does not know who that is either and has no way of finding out.
In my view there must be a requirement on the prosecution to prove who committed the offence. That must be either the person in charge of the vehicle (under 14.3) or the owner (under 14.4). All they have proved is who the Registered Keeper is.
To relieve the prosecution of that burden would be completely unjust (particularly in this case as the defendant did not actually commit the offence). It would be no different to police detecting a speeding offence and instead of establishing who was driving via s172, they simply prosecuted the RK. Section 172 is not available to TOCs (unless they can persuade the BTP to issue them on their behalf) but that’s scarcely the defendant’s fault. Or am I really missing something fundamental?