Same issue, screwdriver (#2 philips) through the hole and nothing changed.
Disassembled to see why. Was due to too much clearance in between the teeth of the adjuster and the plastic body behind it therefore not meshing correctly. Tried with an insulated screwdriver and that worked well. (due to the larger diameter shaft raising the screwdriver tip towards the adjuster teeth.)
6 turns of the screwdriver = 1 turn of the adjuster screw.
Anti-clockwise on the screwdriver to lower the beam.
Sledge wrote:
Did all that, didn't work. Put the screwdriver in through that hole a million times, turned and turned. Nothing changed. Could have unscrewed all the nuts off the Sydney Harbour Bridge by now. So only choice was to go nuclear. All good now.