OK here is what happened...
Was cruising around the other day with it on for a few hours... All was well. Drove the car to work today, but didn't use it. When leaving work, I decided to put her on, and had a mate in the car.
Turned the car on (A/C was off), then turned on the A/C. It was set on 17 and the flow was set to feet and face. It was pretty loud when it came on (full fan), and there was a bit of air coming through to the feet (my mate had thongs on so could feel it) ... There was then like a woooshing sound, and there was no air then coming through at the feet or the two vents in the centre.
Now, the A/C still works, but it only comes out of the vents on the drivers side (near the window) and the passenger side in the same spot. When you try to switch it to feet, there is no change, and you don't hear the vacuum swithing to the different mode. Then when you put it on to the frond windscreen, it does not change where the air comes out ... No matter what setting you put it on, the air only comes out of the two vents ...

I may be imagining this, but it also sounds louder ....

We had a little look at it (but didn't pull anything apart) and don't know what the go is. We took out the glove box, and you can see the switch move when you select re-circulated air, and fresh air, so that is OK ... The temp seems to work, as when we put it up to 30 we could feel it heating up ... What the hell is the problem ?????