Another change has been the seat belt mounting bolts. These were the original bolts and they were too long; when they were fully torqued up they actually touched (and were putting pressure on) the forward diff mount.

I reordered shorter bolts to replace them using the unmarked area on the threads to measure the required length. The discoloured portion has been exposed to the elements, the shiny part has been within the seat belt mount nut.

The new fitted bolts have about 4 exposed threads and crucially do not touch the front diff mount.