I think you are right there Mancunian 103 - I think it is 'Aiding and Abetting'. You are legally required to ensure that anyone driving your car is legally entitled to do so before you give them the keys. You must also ensure that your car is legal before they do.
Why should the driver have needed L-plates? Has he got a licence? If not then you should have made sure he had a qualified driver supervising him. That's not good either.
I don't know the penalties but I'm sure you are just looking at fines. There might be points or a ban though, but it depends on the offences, your record and the magistrates. Whatever happens though, don't ever let anyone drive your car again.