After completing the torch, it wasn't hard to utilise the built-in magnet as a holder as well.
Unfortunately, it is a little bit too weak to hold the lamp all by itself through the 10 mm plastic.
But with a little support from the outside, it is no problem to hang up the lamp on a door frame in the workshop.
Here is the Q-40-20-10-N
that I used, on the left without and on the right with the lamp.