Thanks again for the suggestions.
Turns out the problem was stuck fan brushes (the black things made of coal inside the fan mechanism). It kind of explains why the fan worked properly when removed from the motorbike...the removal procedure changed the brushes position so power passed through.
Now, while the versys fan is sold as a single unit, my mechanic was able to open it, inspect the insides, apply some lubricant and remove some material from the brushes so they can function properly again.
What is really funny is after I posted, I dug out my ebay fan, hooked it up and ran it. I looked at the back, and thought, hey that looks like the indentations for brushes, naw this is a permanent magnet fan, with inverter----Well just shows you, I ain't perfect.
So to explain for those that want to service their own fan, what to look for and how to;
First many carbon brushes, and I suspect the fan is possibly copper graphite or some other combination, have a tendency to foul up. The first thing is to carefully remove the brushes, usually the high spots ( the part sticking in the brush box), are shinny, lightly sand with 300 or 220 garnet sand paper , just the high spots.
A second problem many people make is, most high current brushes have copper pig tails, the tendency is to twist the copper strands, worst thing you can do, as it shortens the overall length and can be the root cause of binding in the brush box.
A third very common thing on power tools and other universal devices, is to install a set of brushes, one of the set has a plastic round pin similar to a lead pencil, behind it is a spring, this is cast into the brush, when the brush has reached maximum wear, that is the same depth as were this pin is cast. All of a sudden the tool stops. You pull the brushes out and see this sticking out of one brush, similar to wear indicators on disc brakes, except this stops the tool.
Some times there are tiny holes for inserting a pin into the brush box, to allow assembly---basically you do need some knowledge.
Anyway , really nice to posts the results for everyone to learn from.