So today whilst I was adjusting the bonnet cable I noticed that there appears to be a dirty big screw through the outer part of the headlight casing into the full beam “bowl”. Can someone explain as to why this may have been done? Both the headlight motors appear to be working albeit they can actually move the headlights much due to said screw.
The 'screw' you mentioned should fit into a plastic housing, inside the headlight, which breaks. If someone has bodged a large screw in there you need to put it right because you no longer have height adjustable lamps. This is a common Omega problem, that is easily corrected without any need for ghetto 'fixes'.
here are the adjusters in order:
left to right:
a complete standard adjuster
the broken pieces of a standard adjuster, which is what they normally look like once you've removed the headlamp and shaken the broken pieces onto the bench
the machined aluminium adjuster that is no longer available
the cheap and cheerful cast resin adjuster that is available and is good enough to fix the problem.