Thanks Mike! Thinking back, there were some problems (apart from not knowing what I'm doing!). There was light fog and the town lights to the south created a pale dome in the sky. Just above this dome, Om Cent was not visible, and my first shots in that direction (centered on Crux) produced almost nothing of the Milky Way. To the south, the sky was black (unlit), but the MW was faint & the dark lanes were barely visible. So trans was obviously not up to scratch. There's actually thick fog in Bright right now!
I did play with levels & curves in PS to bring out what I did. Any more and horizontal lines on the single exposure started to show up.
Anyway, shots just posted by ShaneAust have given me great heart, and I'll keep plugging along!
Cheers -