I've never named our vehicles, but two Range Rovers ago, my grandson refered to our then car as "wacky", cos the plate was WAC. The last one ( now sadly deceased - see towcars "sad day"), was white, so Herself clled her Lily. Her replacement as of yesterday is to be called Jiminy, cos the plate is GYM.
The Royale caravan is called Regina, what else?
The Volvo is The Blob, cos the plate is BLB.
As far as I'm concerned, what they are called depends on my mood and their behaviour!