Simple holder for a 15mm magnet disk (or any circular item).
Hole is provided for a counter-sunk screw to fix to a clip (there isn't enough wall thickness for a female self tapper).
Clip geometry is compatible with the 8mm clip: https://www.thingiverse.com/groups/8mm-clip-system
CadQuery source is provided, and the disk size and depth can be parameterized.
Print upright. I used a small brim, but I think it would stick well enough without.