EZY6158 from Geneva to Bristol on the 2nd Oct, I believe that was a 180 seat plane and if there was a spare seat I didn't see it. There is a chance there was a 4th crew member who stayed at the back but only three names where announced and only 3 ever walked forward of the midpoint.
FYI a nice interior with the new seats and the crew I saw where doing a very good job.