Kart raced by Ayrton Senna up for sale

Bonhams/REX Features

In the world of classic cars it's provenance that really bumps prices up. Looking for a Cadillac driven by Elvis? You'll need to dig a lot deeper into your pockets than for any ordinary Caddy. And if it's a car owned or raced by a famous driver, then you'll need to write a blank cheque if that racer's reputation is big enough.