I searched images of Lennon’s Rolls Royce to double check the license plate, I figured it was shopped. There are many photos with many different front plates, but I found this B&W photo. Maybe “FJB” is legit?
https://www.cheatsheet.com/wp-content/uploads/2020/06/John-Lennon-Rolls-Royce.jpg
Bravo! John Lennon was way ahead of his time.
