ParkingEye have failed to include the mandatory invitation to keeper to pay the charge required by POFA Schedule 4, para 9(2)(e).
POFA isn’t optional. If any of the statutory elements are missing, the NTK is non‑compliant and keeper liability cannot be created. In this case, the NTK simply does not contain the required invitation to the keeper to pay the charge or to name the driver.
That is a complete POFA failure, not a stylistic one. ParkingEye are therefore limited to pursuing the driver only, and as they do not know who that is, the keeper cannot be held liable.
Whether they discontinue before court is up to them, but the legal position is straightforward: no POFA compliance = no keeper liability.
Don't waste too much energy on an initial appeal, they'll reject it regardless. Send something like:
I am the registered keeper.
As your notice is not PoFA compliant I will not be accepting any liability for the outstanding parking charges.
The driver is not known to you and I will not be providing any driver details.
You have two options:
Cancel the notice
OR
Provide a POPLA referral code
I am sorry that I am unable to help you further.
You can finish your appeal with "Many thanks" or if you're feeling mischievous "With measured disinterest".