Ok...
I think it was generally accepted that my first suggestion would indeed 100% work, albeit resulting in a prison sentence and/or driving ban.
However, in the absence of any other idea that will 100% find the owner of the plate, I will offer another way to find them that is less silly and contrived.
1, Go to a scrap yard and buy a wing mirror off any car, black plastic would be best as we don't know the colour of the car your plate is on.
2, Screw the mirror to the end of a cricket bat. Give it to a friend and send them out in their car.
3, Stand kerbside in a 30 zone.
4, Get you friend to drive past you at at least 70mph.
5, As he passes you, get him to scud you round the face with the mirror end of the 'wingbat'
6, Hey presto! ballistics will show the resulting facial trauma is a 70mph hit and run in a 30 zone.
7, When you wake up, tell the police (or write down) that all you can remember is the registration number.
8, At the ID parade, grab the microphone and shout out the registration plate and how much you would pay.
9, See if one of them moves or blinks or something.
HTH