Back end of '79, Monarch painted one of their 720s in P & O cruise lines colours for some flights to meet the ships. It was ex Maersk and had an extra gally just forward of the rear LH door. We removed the gally to get an extra row of seats in but there was no seat rail in the floor. We were told to move other rows forward an inch or two so that the 189 seats would fit. I think some rows were down to 28 or 29 inch pitch.
That must have been very uncomfortable for the longer flights.