From the POC, italicised text added for context
D (defendant) is liable as driver
You're fully sure you've never identified the driver in any appeals or other communication?
If so, the onus would be on them to prove that the RK was the driver and this part of the claim should be absolutely defended, as that seems to be what they are going on.
They can't rely on POFA to put liability on the keeper as they've never served the NTK
Please wait on people with more experience to help draft a response.
100% sure the driver has not been identified.