[morzh]

Well.....I got a new Klein screwdriver; it and PB Blaster, and a bit of WD40 helped.
Not quite the way I thought they would, but they did.

The screwdriver came yesterday.

Yesterday I put a little WD40 on the screw just for good measure.....
Today having the screwdriver I felt ready.
I dripped a bit more PB Blaster on the screw, put the Klein screwdriver in it....no luck. I even think the tip (which I thought on photos looked quite thick and turned out to be razor thin) started to warp a little.
I took out my Kobalt screwdriver that did not work and was twisted, untwisted it some using vise...
What happend next was, well, the screw would not budge, and eventually the screwdriver lunged past it, having slipped out of the damaged slot and almost having punctured my finger, and...I felt the hub rotating around its axis.

I pulled it, and it just came off.
The screw also was then easily removed. It is M3 set screw, a very popular size, so should be easy to replace.

So, yes, it came off and I rewarded myself with a Warsteiner.

Considering I also found and bought the belts for the CD player, not too bad.