Thanks both, really appreciate the insight and opinions.
Panning makes sense -I'm still looking at options for some monitors, so I'm mixing on headphones. I guess the panning I'm hearing on 'phones is not as obvious when heard on speakers.
Reverb is something I'll need to work on - to my ears the tracks sound weak without reverb, so I tend to add it 'as default'. Maybe I need to work on the tracks dry first, and try to get them sounding better before dialling in the reverb.
Thanks
Paul