I lifted the motor off my LUX style mill by strapping it to the roof trusses of the shed via suitable hooks and winding the head down. With assistance to unhook the straps I was able to unhook get the motor down. As I recall it mine could only be pulled out over limited arc of motion due to the pulley not passing through the off centre aperture.
Re-assembly proved not to be a reversal of the disassembly process. I ended up rotating the head through 90° so the motor, still slung from the roof, could be slid in horizontally. Still a considerable faff but by juggling head height and swing of the motor in its sling everything went back together. In retrospect rotating the head through 90° and pulling the motor out horizontally would probably have been a better way to remove it.
However my LUX style mill was a one off with two speed belt drive and VFD motor control bought in by Chester to test the market. No gearbox innards and no oil in the case so no chance of oil leaking everywhere when the head was rotated. Standard one with the mechanical gearbox may let oil out if rotated to horizontal. Best to check, hopefully the book will say.
Clive.