Many thanks for your reply.
Just had a breakthrough after some hours of trial and error!
The problem seemed to be the trackpad on my MacBook Pro. It only works when holding down the button for a second. Other functions in Logic respond to the normal trackpad commands...strange!
I can't select any inputs on the audio channels in the left hand pane.
No drop down options appear...tried re-booting twice, Logic recognizes my Apogee Duet, audio goes in and out ok...I'm running OSX 10.5.8
Anyone had a similar problem?
Any help much appreciated!