Repairing the seat pleats is quite easy.
At least it’s a nice clean job for a change.
First remove the plastic strips attached to the material from the channels on the front and sides of the seat. This gains access to the foam cushion. Lever out gently, with a wide blade screwdriver, try to avoid distorting the plastic strip, as this is held in place with small lugs on the seat channel.
Either side of the seat, going front to rear, you should be able to see 1/8 dia, wire through the openings, lever the front one outwards and the other two inwards, these are the side pleat retaining wires.
Straighten the plug chain, type link, securing the circular plastic discs, the complete cover should now lift off.
Straighten out the pleat bars and repair any material damage, where the bars have possibly come through. Out with the sewing kit!!
To refit, and tension the seat foam. Make up 6 -6 inch long, ridged pull wires, with small hooks to attach to the chains -very light gas welding rod is ideal. , insert wires through into the foam section, slide over the plastic discs, pull through on extra link, insert a small wire/drill to hold in position, remove pull wire, open out chain link as per original, and then remove temporary retainers.
With the side pleat bars, you might find the front clip fails to hold in position, or forces the centre ones out of the retainers. If you bend the last 2 inches of this straight section inwards, this should hold all three in the correct position
Refit the plastic strips, aligning the material seams with the foam side wings as you go.
Quite agree folks – Monza looks far better than Le Mans.