Stop referring to anyone identifiable as "the driver"!!! Is the PCN you've shown us the Notice to Keeper (NtK) that has been forwarded by the lease (lessor) company to the "Hirer" (lessee) or is it the Notice to Hirer (NtH) sent to the Hirer (lessee)?
Aside from any admin fee charged by the lessor, the Hirer cannot be liable for the PCN. Neither the lessor nor (not so) Smart Parking) know who the driver is and it should remain that way. Smart are not allowed to presume nor infer that the Hirer must also be the driver and the Hirer is under no legal obligation to identify the driver.
So, has the Hirer received their NtH yet? If so, the easiest way to get rid of a (not so) Smart Parking PCN is to submit the following appeal (verbatim):
This is an appeal by the Hirer - No driver details will be given. Please do NOT try the usual Group Nexus trick of asking for driver details in order to get around the fact your NtH does not comply with PoFA. As there is no Hirer liability, therefore, liability cannot flow from the driver to the Hirer and so, is an automatic win at POPLA. Please cancel the notice or issue a POPLA code at which point you will auto withdraw.
Smart do not issue PoFA compliant PCNs and so, as long as the drivers identity is not revealed, will always lose at POPLA. Also, Smart never have a valid contract with the landowner to issue PCNs. They make
all their money from low-hanging fruit on the gullible tree who know no better.