So I pulled them off and found that the 8mm headed bolt IS the adjuster, but it had frozen up with dirt.
Heres how to service them so they work again...
Remove 3x m6 bolts, swing Light out to access wiring...

Unclip cable from side, turn & remove back cap, disconnect the H3 wiring and the Light is out. Remove the adjuster gear ass'y with 2x phillips head screws...

Flick the cover off the gear ass'y, put it a bucket of nice warm soapy water, clean all parts with a toothbrush, dry and reassemble with some plastic-friendly grease...

Refit gear ass'y cover and refit ass'y to light, refit light.

Now you should be able to adjust the foglight aim!