Originally Posted by
Max Tow
"I don't see any asymmetric top contour". Really? If you look closely, there is a definite angling in of the right side of both the seat backs in the photo (i.e. to the occupants left side) which is presumably to fit a tight fuselage or canopy side contour. Possibly the reported joining might be a red herring, i.e. these might be two individual pilot seats which have been modified, otherwise why contour both? Plenty of photos online of Mosquito pilot seats with similar backs but hopefully someone from Salisbury Hall will come along to confirm or deny!
I'm not so sure about the asymmetry, having looked at all the photographs. The seat back is not in a single plane, but inclines towards the neck of the occupant, roughly, and then away. This means that when the seat is looked at from an angle, variation in the z-plane looks like assymetry in the x-plane, but when compared with other photos, you can see that this is an effect of point of view.
I'm not sure I've got z-planes and x-planes right, but if you look at all the pictures, you'll see what I'm talking about.