I lied!
Here's the AutoStitch version at least... complete with automatic black background, and exposure compensation.
Interestingly the final image is under half size of the original one I did - only 1400 pixels wide compared with over 3000.
I suppose there's settings in autostitch to change that if I took the time to look! This is only the second time I've played with it... I'm impressed with the way it handles exposure variation!
Very quick and painless!
Al.