The square paralell light has worked a treat. Thankyou for the idea. And that's a neat site, loads of solutions there. I don't think I can even think about volumetric. This image is going to take for ever as it is. I am turning my background poser figures into 3ds to try and save size. It has 34 lights so far, and will end up with up to 20 poser people, and that's without props. May have to do 2 takes.

The greatest part of wisdom is learning to develop  the ineffable genius of extracting the "neither here nor there" out of any situation...."