Bought a '05 MCS and dealer could not answer the question! It appears that to just get flow-through ventilation [what one would want with windows down, for example] that you hit the fan button, which seems to turn off the automatic climate control and air conditioning, then you select an air distribution button and then you turn down the temperature control as far as possible. The manual does not address flow-through. Is this how it works? Sorry for the stupid question.

 

Yes.
If you set heat to "LO" it'll stop any heating. Then also turn off a/c so there's no cooling either. Finally adjust the fan to the air flow you want (of course make sure recirc isn't on)

On the older '02/'03/etc MINIs, turning off the system left the heat part unadjusted so very hot air would blow through the vents if it was heating prior to turn off - don't know if the '05 is improved here (it is improved in that it doesn't blow freezing cold air while the engine warms up)