Well, now you've put time pressure on this (in the other thread). If only that were some kind of help . . .
Okay, here's my guess, based on the fact that the only license plate I can remember from any film is Goldfinger's AU 1. Could the "passengers" refer to Goldfinger's Slazenger 1 golf balls? That is, AU's 1's? And we know there were at least two because he lost one and played a second?
I've got it! Bond and Mr. Solo, who were both in Goldfinger's car!A particular licence plate would be an ideal clue for at least two "passengers" that rode in this vehicle.
You are both so close....