It helps to also remove the 2 hollow adjustment thingeys on the bottom of the light assemblies.
When reinstalling, get the light in and start the adjustment thingeys back in the holes,
position the light ( after reconnecting the harness and installing the marker light ),
tighten up the top 2 light bolts, then
screw the adjusters up until they just contact the mounting flanges, then secure with the bottom 10mm bolts.