[Bob 1967]

Okay ,so here it goes.
Bench:
Front clips are a straight pull up to disengage.
Rear clip is not easy to access ,but it is basically the rear of the seat bottom frame , made from 6mm or 1/4 inch round bar (which has a certain amount of spring to it).
This is hooked around a fixed bracket fixed to the chassis.
Pushing on the wire close to the bracket with the wooden handle of a mallet was sufficient to disengage it and enable bench removal.

The upper section has two loops (at the bottom) hooked on to metal clips attached to the body .
I bent the clips enough to unhook the loops.
Top of seat is attached in a similar way to the bench, but with two clips.
The bench method would not work here.
Knowing the springiness of the seat frame, I used a justifiable amount of pulling force on each side at the top to ease the tension on the frame then push (at the cushion) each side in , up and off .
Job done.