Removal of headlight switch knob

[1963turnerjohn]

I am fitting a new headlamp switch to the 1941 Super Deluxe and upon looking at the original unit cannot see how to remove the 'knob ' so I can remove the knurled nut and slip the switch out of the dash.

Does the whole knob and shaft come out of the switch housing as a unit?

I thought there may be a small Allen head set screw holding the knob onto the shaft.

Thanks
John