Discorde
You are so very right about the Ambassador (more likely Elizabethan at LHR of course) a very distinctive noise compared to the big American radials whether airborne or at full TO power . I always thought they cannot have been easy to fly because of the seemingly very small cockpit windows. They also seemed exraordinarily close to the ground ,with Darts they would proably have got a decent amount of market share from the F27 which was succesful globally, not sure if anyone but the Brits flew the Ambassador.