I can confirm from an insurance point of view that any third party claim would HAVE to be honoured in accordance with the RTA.
We would be liable for the third party claim in full ,and would seek recovery of the costs from our policyholder.
The only time that we can realistically avoid being held liable for any third party claim is if the vehicle was not on cover at the time of the accident (ie policyholder takes out a policy within hours of having an accident so we show as insurer for that day), or if the vehicle is stolen and the driver/thief remains unidenitified.
Also, David is quite correct - we check all licence types held by our policyhodlers when the policy is taken out, and also on certain types of claim. If our poliycholder holds an auto licence, but was driving an auto, we will repudiate the claim for driving other than in accordance with their licence.