Grey , 06 plate, Saloon A6 C6.
You can trace last/current registered owner from DVLA. There's a fee for it also, £20 I think. Need to send them form (don't remember which one) with filled details, why do you need the info on the driver and they may release this data to you.
Off top of my head, there is a choice for these answers as that he "was involved in a collision" with you or something like that. That way they might incline towards your favor.
I did this few times myself but unsuccessfully as the reason I was submitting was not significant for them.
You may be lucky tho.