Hi Lisa!
Thank you for you're reply. I'm going to attempt some of the suggestions you made like tinkering with POVRay. I have put some thought into a solution, and the most obvious one that came to mind was the same one you mentioned which would be retexturing the specific parts I've coloured to what they should be when rendered either by tinting the texture or of a course a seperate texture as a whole.
However, I don't think there is actually a problem with the lighting in POVRay when it renders. It looks correct to me except my colours that I have used the palette in AC3D to paint are just omitted entirely in the render.
I've attached another image so you can see what I mean: this is the default settings (since I haven't tinkered with them at this point in time) render of the model using POVRay. You can see that the "road" that I painted has vanished. Its not like the road has been whitewashed out by the light either, its just the colour is gone.
Anyway, I'll see what I can do meanwhile.