I found another photo, this time it's the 1993 Livery on the Tour of Flanders Rally.
Here you can see 4 rubber grommets protecting the threaded holes in the bonnet, but this time the wiring connector is routed through the bonnet to bumper gap.
On the car behind, you can see that the lights attach to metal backplates which attach to the lamp-pod, and provide the fixing holes for the lamps to attach to.
