to claim any car you must make every possible effort to contact the owner, check any of the homes close to it, contact the land owner where its parked, aswell as contacting the police to see if they have any knowledge of the car, it could be stolen etc,

then apply for the log book, it i'll take a while to do it all.

it has been done by a couple of people on here, if you can find the threads, you could maybe contact them and find out how they did it