This is what it looked like beforehand.
And this is what it looks like now.
I was able to increase the height through by fixing a batten to the stainless steel cross member that is hidden and forms part of the GRP shell structure. Some people have removed this but I am inclined to keep it. By making a small slit about 50mm either side of the GRP moulding I was then able to bend it up and attach it to the batten. Once the glue has gone off I will be able to remove the temporary fixing screws. I have shortened the ambulance headlining trim to meet the join which will then be covered by an aluminium carpet joining strip (or similar) to finish the job. This modification has given an extra 5"-6" of height going through.
Behind this GRP trim was the path of most of the ambulance loom. These 2 bundles of wires needed to be removed to permit the GRP to be folded back. Here they are. In this picture you can see the GRP that I have folded back.
Unfortunately in the process of culling these wires I lost my central locking to the side door. Ho Hum! I'll sort that out at a later stage. The top A/C still works though :-)