When we first had the VC10K2, we had forward facing 'Comet' seats. But then 'They' decided that we had to have the normal rear facing seats....
However, quite often on TTF pond-hops and the like it wasn't unknown for seats to be rearranged so that we had a 'club' layout with a rear facing triple, a table and a forward facing triple. Useful for next leg planning, dining and for ground crew to consult manuals when fixing the inevitable snags which often cropped up.
The reason for the red marking around the pipe in front of the first fuselage tank cell was because one variant had the fuel tanks rather closer to the cabin door than the other - I think it was the K3? So if people opened the door and went into the tank bay having been used to the other, they could end up with a face full of fuel pipe. Solved by thick sponge rubber and dayglo strips by our ever-inventive ground crew!
When the K4 was about to come into service, as it didn't have any fuselage tanks (to save cost - in any case, unlike the K2 it had a fin tank), a paper was written proposing to fit more seats. Viewed with horror by 'Them' as that would have probably led to some C1s being scrapped. But 36 seats in 6 'club' layouts would have been rather civilised!
Dear old Vickers FunBus - an utter delight if rather noisy and thirsty. Like many of the crews!