Thanks for the link; interesting but my main problem seems to be the length of time for printing. I have been doing some more tests over the weekend and 2 things seem to have been learnt;
1) I need to put a fan on my printer as exposures are still going to be in the 25-30 minutes area and everything gets hot which I think is the cause of silvery-metallic metal apparently being formed on the paper surface.
2) All my tests are empirical as I do not have densitometers etc, so it is a longish process.