Ok, they are definitely out of time to transfer liability to the keeper, but you need to be careful not to say I parked...
Appeal as keeper only, declining to name the driver, and pointing out that they have failed to issue the PCN within the required timeframe (14 days) to allow liability transfer, and you are therefore unable to help them further.
They may well refuse, but a subsequent appeal to POPLA will probably get it quashed.
This assumes that a windscreen PCN was not served?
