I have done all of the above Mr Linzey. I have even dismissed using the stage tool, and reverted back to extruded polygons, which used to work swimmingly well, applied a renderworks texture, but am coming up with the same output.
However, when I start a new drawing and recreate the scenario, it acts as it should, solid, no light passing through.
What setting have I turned on that I shouldnt have?
thanks again