Alan, for some reason when I import one of my structure models into a fresh scene it doesnt render in Maya Software (black) but it renders in Mental ray. However when I apply a new lambert it renders in Maya Software. I know I'll be rendering in Mental Ray but it would be nice to know the reason and get it rendering in Maya Software as well. In case it's needed.
WORKED IT OUT! I'm an idiot! mia_material_x_shaders dont render in software obviously! Crisis averted