Jet Assisted Chevy.
Two feature film special effects experts test the bizarre claims of urban legends and misconceptions, using ingenious experiments to assess the facts.

I think that's close to the exact description that Tivo uses for US reruns.

Jet Assisted Chevy was, I believe, the very first episode. Some have been describing specials. There are some specials, but each episode consists of multiple myths. Wasn't the Chevy episode one of the ones I sent you, Andy?

Anyway, I'm glad you've finally got it over there. Otherwise I would have had to start a Mythbusters UK distribution business