Shortlived (4 episodes) 2006 drama starring Patrick Stewart (as Dr Ian Hood) and Ashley Jensen (as Rachel Young), and filmed in Manchester. Chronicling investigations of dodgy scientific experiments, it was perhaps ahead of its time in treading ground now covered by Fringe and a CBS remake starring Rufus Sewell as Dr Jacob Hood.
Episode 1.3: Kryptos
Sees a troubled scientist aboard what looks like a Stagecoach Magicbus Leyland Olympian.
Later in the episode Dr Hood runs and boards a silver/blue Dennis Dart/Plaxton Pointer. We don't see much of this, either, other than a partial fleetname: