Just bought this to play with.

[Gillstay]

Don't know if this helps, it's for a one piece crank but sounds like a ST BB would remove like a standard one:


View: https://youtu.be/cz7aQCC1kgE

Yes, I looked at that and his is a bit simpler, but it my well just be that I can wind that side off. I was wondering more if anyone had experience of the one I have. Don't like breaking bits on nice old bikes.