I made the door panels as below.
I stripped an old door card as a template for the holes and the shape.
I then clamped it too a piece of 4mm marine ply, drilled the holes and cut it out.
I drew on my design, marking out where the arm rest would go, and spacing out the 40mm wide pleats or columns, underneath the leather. The top padding of the door card was achieved using 4mm thick rubber foam which I attached with spray adhesive. The pleats were made by using 40mm wide self adhesive foam, which can be bought on a role, from Ebay.
Once all the 'high' points had been created, using the foam, it was time to fit the leather cover, also purchased on Ebay @ appox £50 for both sides. I sprayed the central seam with the contact ahesive and glued the cover in place. I then spayed the pleats, and glued them down about 100mm at a time, going down the panel from the central seam.
Once all of the low spots had been glued, I wrapped the edges around and glued/stappled them at the back of the panels.
to get the definition, or sculptured effect in the panel it was important to ensure that the leather was pressed hard into the 'low' area to ensure adhesion, and this was done by rubbing across the top of the leather into the groves.
Hopefully this description and the earlier picture shows you how it was done.
Best wishes, Kev