Another blower issue..

[Zcubed]

Astra J 2010 1.4T Elite climate air direction selection-mind of its own problem!

Hi everyone,
I have a 2010 Astra J 1.4T elite with dual zone climate control.
In AUTO mode, everything seems to work correctly, controls temp and directs air to windscreen vents, middle vents and footwell vents.
However if you manually select the air direction (the manual says all combinations are possible) by using the selector buttons, the individual buttons light up, the display shows that they have been selected but the actual air flow direction does not go where selected and is pot luck where it comes out, irrespective of your chosen route(s).In fact it is not even repeatable but the combinations seem to change every time you reselect the air direction.
This has become an issue, due to my wife's eye condition, where she mustn't let air blow on it, so generally she wants to turn the air off to the windscreen, but with the manual air direction not working this isn't easy.
Also if you put the ignition on, fan off and select the buttons and listen carefully to the actuators, the windscreen & footwell sound slick but the central vent makes a odd sort of sound-don't know if this is normal or not?
Have been reading up on some previous posts and was wondering if it could be the control module or stepper motor at fault?

Any ideas would be much appreciated.
Thanks