Clunking/grinding noise when I operate the switch from 4WS to 2WS (visa versa), when the car is stationery (engine idling) to when start reversing; then the noise would stop; and then I would hear it occasionally as I'm driving (slowly) and when come to stop - (not as loud as when the car is stationery/reversing). Any clues to what it might be?

did it do it before you stripped the motor?

I haven't touched the motor! The noise's been apparent at the time I bought the car a month ago. I was in the dark when I bought this car, as I didn't know anything about 4WS.

sorry! confusing you with someone else, sounds like it's time to strip the motor and grease it up.

Sounds like someone else has stripped the backup motor and left some flotsam inside. There's a tiny ballbearing on the end of the shaft which is difficult to get back into the motor housing past the magnets, and also a little aluminium spacer which broke on mine when I stripped the motor. I also had to drill out and retap some of the mounting screws. Time to bite the bullet and put yer overalls on!

I'm a novice to the 4WS! Where can I find the backup motor?

First off check the 4ws stuff in the files section of the 4ws club. Jack up the back of the car (don't forget to use secure BS1009 - standard axle stands - Uncle Sam) and remove the teatray that protects the 4ws stuff. Best to remove the gearbox and motors all of a piece (4 bolts + disconnect wiring connectors inside the boot) and then try the motors on the bench - they should both run in situ without dismantling from the gearbox. The backup motor is the one with flat sides, on the driver's side.