Before I could start with fitting the gearbox cover the bulkhead and driveshaft tunnel needs to be fixed.
For some reason it looked like they have removed the gearbox from the car compartment, and needed some extra room. They used a chisel to open up the bulkhead and drive shaft tunnel for about 4 inch.
In the direct neighborhood of my home there is a jaguar garage situated and I could borough one from them. It was a cover from a XK150 but they should be interchangeable and could be used as an example.