Series 3 Windscreen/cabin direction valve

One of the jobs that I still have to do when I get home is to fix the cabin/windscreen direction valve. I move the lever and nothing happens, I think it was stuck in cabin heat mode unfortunately.

Can anyone give me some pointers as to what it's likley to be and what I may need to replace?
I'm still at work and so won't get back to my series for 6 weeks.

its not really a valve, its just a wire that lifts the flaps up and down that let the air out of the bottom vents. might have come off at the dash end. or the cable might have rusted to the sheath. flaps may have rusted in the up position.

have a look to see if the flaps on the lower vents are lifting and closing, if not then you just have to take some of the dash off to see what is going on. could also be the hose to the windscreen vents have come off