Quote - I have set all the gather node MaxDist parameters to 500 but this has not helped. Only objects that are quite close will pick up the colour of the props and 'reflect' it.

I had a similar problem. My Max Dist wasn't nearly enough.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2716669

You might want to try a value considerably higher than 500.  Bagginsbill explains it in this thread.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi