Welcome to the forums.
This does seem strange indeed.
Please take a screen shot showing the track headers and post it for us to have a look at.
Thanks for the quick reply Eddie,
Screen capture as below if it helps. Although I really think it is connected somehow with the properties of the audio track (if I could see them). I tried a little experiment, I can select the clip and adjust as normal if I drag the audio to track 'Audio 5' in this case. If I drag it to any of the other tracks prior to 5, it won't select or adjust.
screencap.jpg 144.5 K
I just answered my own question after messing around with it for a third day! Just in case anyone else comes across this too, it's a matter of clicking on the keyframes on the track header and choosing 'show clip volume' or 'show clip keyframes' and not 'show track keyframes' or 'show track volume' as then you won't be able to do anything with the clips dragged onto the timetime (except change overall track)...
It sounds so obvious to me now, but it had me fooled long enough to go searching everywhere for help.
It is best to set your keyframes on the clip itself.
Because when moving the clip the keyframes will not move along with the clip.