Hi Toby thanks for the suggestion. Gave it a go, concentrating on adding more emphasis on the incoming wave, and I admit, I think your idea has strengthened the depth. I was very happy with my first attempt, but feel this final(?) edit is better.
I didn't alter the contrast as I copied over the original tiff with the last attempt, and didn't have the fire to start again from raw (yet, but when I do some time I'll use the contrast more selectively. I seem to mostly only use global for most of my processing, but maybe I should change this approach?)
Scott.