Andy, spoke to the guys in the factory today.
There are two lugs on the top of the headlamp mount
One at 11 o’clock and the other at 1 o’clock.
The rim is lined up and the rim located on the two lugs and with the bottom screw hole.
The rim is then given a gentle bash with the heal of your hand. There is an interference fit around the headlamp mount.
Screw the bottom screw in and job done.
I hope that helps.
Send me a private message with your email address if you want me to send you the 3 photos I took this morning.
Good advice but try and ensure the securing hole is lined up with hole in mount before committing to a firm downward push. A small torch shone in the gap helps with this. If not quite in line the rim can be nudged round a little.
I've removed and replaced mine three or four times now but it doesn't get any easier.