They ran on the 58 route. The reason they never apeared on other routes was because they couldn't actually get around the corners (i jest not!) Maybe this is why the 73 is the only route too be trialed? Nottingham gave them back after their trial (much like that one train company recently did) I'm guessing because having busses tied to one route and one route only is a bit silly really.
To be honest though... I'd rather the Bendy Busses to the Tram system they've put in. you know they're 2 years over the projectd ready date and there's allready been 3 car related accidents just on the system test runs becuase they just can't stop quickly engouth. They had to re-lay a part of the track in the town square becuase it kept de-railing the trams! The greater of two evils i fear!