Oh, one little postscript to the story that some of you might get a kick out of:

When I was a kid I used to watch that Gerry Anderson show Thunderbirds (Yes, with the puppets). Even had a Thunderbirds coloring book. Don't ask me why, but my favorite was the bright yellow Thunderbird Four , which was an underwater rescue vehicle. I always thought the Proton shared a resemblance to one of these.

The license plate I received today contained the letters UDV, which is also an acronym for Underwater Demolition Vehicle. Just one of those serendipitous twists of fate.