The upper dashboard rail (above the instrument gauges) was absolutely fine. The lower dashboard needed a bit of attention though.
The normal procedure was carried out; removing all the rust and old paint, and then repainting. Here's the lower dash before and after:
The function of this lower dash is mainly to funnel air from the heater to the upper vents. It also hides the wiring going to the ignition and instrument panel, and provides a "parcel shelf" and convenient housing for the centre console instruments.
Unfortunately when it came to reattaching it to the bulkhead I discovered that although the refurbished upper surface was now fine, the main body of the thing (under the vinyl covering) wasn't. Due to water ingress over the years, the very thin steel used in its construction had rusted away in places - in particular where the screw-holes attach the panel to the bulkhead. By the time this was discovered, I was in a situation whereby I needed to get the vehicle reassembled fairly quickly, so I wasn't able to resolve this issue to my satisfaction. When I have some more time the lower dash will be removed again and replaced; I may even manufacture something myself. For the time being though, it does the job.
The plastic housing for the auxiliary switches was in poor condition, so using some aluminium plate I made up a new housing. This also enabled me to squeeze an additional switch into the space! The switches from left to right are: hazard warning, front spotlights, rear work light, and interior light.
The separate switch for the instrument panel lighting was removed; instead I wired the instrument panel lights to come on when the vehicle light switch is on. (Details of the trials and tribulations of doing this is covered in the section dealing with the instrument panel). The rest of the photos on this page were mainly used as references for reinstallation. Here's the wiper motor still on the removed bulkhead:
Auxiliary switch wiring, steering column stalk wiring and ignition wiring: