[knobtwiddler]

Thanks, all - much appreciated.

There isn't much to see. It is a 300mm x 300mm sheet of powder coated steel. The cap-head screw is flush against it. The brass spacer is on the other side, in a dense nest of circuitry, which cannot be disassembled without removing said screw, thus creating a chicken and egg situation in that regard.

Maybe a Dremel disk, but instead of trying to cut the head off, damaging the enclosure due to the.flush nature, I could attack it vertically, milling an x into it??