Okay, looks like we have a solution. I disassembled the center stack this morning to take a look at my heater/AC control cables. This involves removing all of the trim, the radio, etc, and then pulling down and out on the piece that has all of the heating a/c controls and dials. I wanted to see if all the cables were connected, and if so, were they moving freely.
They were, on both counts
Okay, so I got out the Bentley, and looked at the diagrams of which cable did what, and where it went. I figured this end of the cables looks okay, it must be on the other end of one of them that my problem lay.
But wait!! There's a nice explanation in the Bentley of how the three cables attach to the back of the panel, and guess what? They are color coded. See where this is going??
Yep, somewhere in this cars past, someone mixed up two of the cables.
Page V87-12 of my Bentley shows that the Central Flap Cable (#1 in diagram in manual)has a BLACK sleeve on the cable, and should be attached to the lower of two levers.
The Footwell/Defrost Cable (#2 in manual) has a WHITE sleeve and is attached to the upper lever. (the one closest to you when looking at it from the top.
if these two are reversed, you don't get complete closure of the fresh air flap, and you can't direct air to defrost or footwell. All air flow goes to the dash vents.
Resulting in cold feet, and an unhappy wife. All fixed now, and I treated myself to a new headunit while I had it all torn apart.
So, in the end, warm feet, and new tunes.