2) If someone was bleeding in the car, before it went over, and it hadn't yet dried, is it possible the blood could be found in the car? Any traces of DNA at all? Or would being in water for a few hours just wash everything away?
3) If the police find the car - where would they take it? The story is set in modern day England. Is there somewhere they get taken, in case they need to be kept for criminal investigation? Would they just search the car then take it to any old car dump to be trashed? ETA: If they believe the person to be dead, how long would they keep it there? If they thought it was just a case of someone losing control on the road and accidently drove off the cliff.
4) If no body is found, but the police believe the person is dead and been washed out to sea - how long would it take for them to declare this? Could it be quite soon? Do they have to wait years? Could a girlfriend - not a fiancée or wife - have any rights to ask he'd not declared dead, if she believes him to be alive? If the only other family member is a sister, could she ask he be declared dead? How long before a death certificate is issued in this case?
ETA: I completely forgot to say - he's not a British citizen. Both the missing/dead person and the girlfriend are American, and are in England studying/working.
Thanks for any help/suggestions!