another possibility, I had a winch that would click but not turn and it turned out to be the clutch was stuck inside the drum tube
That's not a clutch - it's a brake. All 'clutches' on common low lines are just 'freespools, primarily usinhg the sun gear as the free spool and some kind of simple locking devices. There are oddities to this - Ramsey REP's for example
Brakes jamming up in the drum are a common occurance - usually becuase they have been put in the wrong way round
Clicking like yer man describes is electric. Bit like on a vehicle with a starter problem
Always start with the earths
Then move on to the permanent live
Then the switched lives
Finally the LV supply from the control
If it's the motor brushes you don't get a clicking as such unless they are absolutley shot or rusted up to helll and back so as to be earthing out through the corrosion. Damaged motor brushes just effect the motor speed and pull...
What you might have is coorosion in the main motor effecting the armature.
Some of the branded stuff like the atlas doesn't have a bearing for the motor shaft on the end plate, instead they have a bronze bush. I have known these to get very badly corroded before and jam up the motor shaft movement