Many thanks to David Clunas and Adalberto Tiburzi for re-processing my PAD of December 6th. It has been really interesting to see others process my picture. Perhaps this will happen increasingly in the future of PBase?
David has certainly achieved the improvement that eluded me.
"Thanks John, interesting image to work with.
I copied the blue channel and then went for a natural conversion using channel mixer and levels.
Converted this to grayscale and then copied the blue channel over the top of the image. I then adjusted the layer settings. Converted to tritone, made a few dodge and burn tweaks and rotated the image to straighten the verticals.
Maybe a little dark, depending on your printer and screen settings."
Alternative re-processing by Adalberto Tiburzi :