Thanks Folks,
I used Vallejo's Still Water Effect - about three or four very thin layers - partly due to a few too many thumb prints when testing if it was dry. I did paint the base of the beck Games Effect - vomit green with a few stippled patches of white for the eddies. I would do this again but probably make these base colours more pronounced and a more dilute amount in the first layer of the water effect.
As to longer-range photos, I'll have to take some more and post.
Stuart