Hi guys thanks for the ideas so far.

I have been monitoring the active nodes like a neurotic mother when I start rendering cos I just want to see it work :)

Strange thing, last time I left network rendering on (accidentally, I'd given up for a while) I came back after a while to see that the ESXi box had actually been rendering some of the image!  Thing is now I see it is unworkable because I've deployed a lot of camera-facing JPG texture particles and it seems different machines render them slightly differently from eachother.  I could actually visibly see the squares which had been rendered by the active node. :)

I tried something else - installing Carrara on these boxes and rendering a test frame of the scene.  Netiher box could manage to render a single image, encountering a memory allocation error (even with spooling way down to 10-20mb and the exe's laatido'd).  I thought the i7 laptop would have been more powerful but I'm starting to think the scene is just doing too much for these other boxes that aren't quite a supercomputer.

I'll try again once this scene is over with with something simple.  One of the preset canyons or something, and I'll see if the collapse of CPU processing is actually due to my ambitious animations.... :p

Ta chaps,
Matt