Thanks Mary.  I'm amazed at at sheer number of tutorials etc. at Geek at Play. I'll be spending a lot of time there.

I was playing around last night and was able to create a similar scene to the one in the tutorial I had been following, but I did it by painted the materials and then using the eco-painter module to add an ecosystem to selected areas.

It was looking great until I started playing around with the atmosphere, something got corrupted, it crashed and now the scene won't open :-(

Oh well, win some, lose some.