I never really asked.
It's not uncommon for a rare one of a kind motorcycle to show up at the races. We are friends with the guy that owns the only Britten V1000 race bike released to the public with serial number 0001. There's only 10 in the world and only one that was sold to the public before John Britten died from cancer.
Last race this rare one off build sidecar showed up at the race.