Took everyone's advice and on my way home last night, allowed the windows to all mist up (to prove the theory) and then hit the button to deactivate the recirculation thing and guess what, the windows demisted. Hadn't realised it would have made a difference, thought it was all about temperatures either side of the windows and would have never thought of moisture implications.
Simple, quick (and possibly obvious to some) solution but effective....
Again, LOC has come up with the goods!!! Thanks everyone...... I've put the A/C to bed for the winter so its gagging for use next summer!! B)