Kurt, I have an answer to your mystery:
By the looks of all those bends, kinks and curves, the previous owner (or a rogue thief) had a few too many pints at the pub, before attempting the ride home (or to his den of iniquity). Multiple crashes occurred that night after pub departure, but the PO (rogue thief) just kept on going, each time righting the bike, brushing the road grime off his trousers, and pumping towards his final destination.
Once arrived, the PO (or rogue thief), still in a haze of alcohol induced stupor, held onto the shed wall for balance, and exclaimed while admiring the sturdiness of this classic British Roadster,
"By golly you are a jolly old Sport!" And immediately scraped off
Superbe Tourist and applied the current downtube decal.
