As the car is leased to you, and you are not the Keeper, you are the Hirer, the way the lease company should deal with this for them to receive the Notice to Keeper (NtK) and then they transfer liability to you by providing APCOA your details and a copy of the lease and liability declaration. You then receive a Notice to Hirer (NtH) from APCOA which is very easy to deal with and you won't be paying a penny to APCOA as long as you do not identify the driver.
As for the admin fee from the lease company, you may not be obliged to owe it to them, depending on the wording in your lease agreement and references to invoices from private parking firms. This is NOT a "fine" or a "penalty" issued by any sort of "authority". It is simply a speculative incline from an unregulated private parking firm for an alleged breach of contract by the driver.
As you cannot respond to that Notice to Driver (NtD) as the Keeper, you are kind of stuffed unless you admit to being the driver and pay the charge. The only saving grace is that if you don't pay it, apart from loads of useless debt recovery threatening letters, nothing will happen because APCOA do not litigate. You can safely ignore all debt collectors as they are powerless to do anything except to try and intimidate the low-hanging fruit on the gullible tree into paying out of ignorance and fear.
If you can persuade the lease company to give you a Letter of Authority (LoA) to act on their behalf as the Hirer, then you could appeal it as the Hirer. However, unless you get that LoA, you cannot do anything until you receive an NtH.
It is very easy to appeal once you have either an NtH or LoA because the driver is not identified (no legal obligation to do so to an unregulated private parking firm) and they cannot transfer liability from the
unknown driver to the
known Hirer as the location of the alleged contravention is on land that is not relevant for the purposes of PoFA 2012.
This would be the appeal if you were the Keeper or to receive an NtK or NtH:
I am the Hirer. APCOA cannot hold a Hirer liable for any alleged contravention on land that is under statutory control. As a matter of fact and law, APCOA will be well aware that they cannot use the PoFA provisions because TfW Newport Station is not 'relevant land'.
If the TfW wanted to hold owners or keepers liable under Railway Bylaws, that would be within the landowner's gift and another matter entirely. However, not only is that not pleaded, it is also not legally possible because APCOA is not the landowner and your 'parking charge' is not and never attempts to be a penalty. It is created for APCOA’s own profit (as opposed to a bylaws penalty that goes to the public purse) and APCOA has relied on contract law allegations of breach against the driver only.
The Hirer cannot be presumed or inferred to have been the driver, nor pursued under some twisted interpretation of the law of agency. Your NtH can only hold the driver liable. APCOA have no hope at POPLA, so you are urged to save us both a complete waste of time and cancel the PCN.