Yep the ducting was gone so I didn't realize what it was for.

I have nothing to add......just would like to thank Colin for remembering how to spell through properly!   Don't see it enough these days

It seems like you are talking about the cabin ventilation duct. The 90's Minis have a duct that comes from a triangular plastic piece behind the left corner of the grill that you can see here. The plastic tube/duct goes over the radiator opening, through a little support circle, and to the firewall, where it then serves the heater and dash vents through smaller hoses. It has nothing to do with the cooling of the engine. 

Yep your right, it pulls the air from the grill and blows it thru the radiator and out the fender.  I guess if you cover the grill with those big lights you still pull air up from underneath.  I really feel my large oil cooler makes a definite difference in keeping the engine temps under control.

Re fan orientation -

The fan is more efficient if fitted the correct way (the blades are aerofoil shaped).  If the other way round, it will still suck the air out of the engine bay, blow through the rad, and into the wheel arch but will be less efficient.

It will also be too close to the rad for comfort.

99% of cars the air is "rammed" in the front, through the grille, through the radiator and into the engine bay and out the back.

The mini has a similar front to back flow - the air goes thro' the grille, into the engine bay, then sideways thro' the rad and out the side.

That's it, thanks, drivers side fresh air source.

Now you got me wondering, I'll go check the fan blade orientation.  Air comes thru the grill, flows backwards thru the radiator and out the fender??  Hmmm, I guess I always thought it was the other way like a typical radiator which was why owners didn't have cooling problems when they covered up half the grill with big lights.

Drivers side cabin air duct.

Take a look at this diagram, see if you can match the things you see to numbers:

https://www.minimania.com/catPage/8-54/8/54/1/Heating-and-Fresh-Air-Ducts-Hoses

Very difficult to imagine without a picture.  Where does this little duct go in the engine bay.
Or is the fresh air duct to the ball vents in the dash ?

Does your car have the later front mounted rad or the side mounted rad used since 1959.  If the latter, air for the radiator comes through the front grille, into the engine bay, through the rad, and out through the LH inner wing.

My 93 Mini Cooper:  Pulled the left front tire off today for another issue.  Here's my question.  There's a large opening for the radiator that looks normal until I saw this little duct that was tucked up in the top of the fender.  Sorry I can't do pictures.  It's maybe 10" long 2" wide shaped like a "T".  What ever hose was supposed to be there was missing. My first thought was I wonder if there was supposed to be a big covering over that opening in front of the radiator and this was supposed to supply ram air from the grill opening.

Went to my Haynes manual but couldn't find anything about it.  I should mention that I have an oil cooler and have never had a overheating problem sitting in traffic on a hot day in Oregon.

Thanks
KO