Thanks guys for all your positive comments - always welcome
On the rays front, I'll post both .tgd files later today when I get home (assuming I remember, be patient with me, I have a memory like a sieve at the moment!).
In the mean time, as a brief explanation, I merely messed around with the cloud pattern seed values until I found one that I liked, i.e. one with a big break through the middle of it, then I just positioned the sun behind it. The sun settings are the default ones and the cloud settings are based on the ones described in
http://sotecware.bttec.org/tg2wiki/index.php?title=Tutorial_Wolkenwand (I had to rely on Babel Fish for a translation as I don't speak german).
In order to reduce the graininess, I set atmosphere to 256 samples and the clouds themselves to 200 samples. Unfortunately that meant that each render took just over 24 hours.
Hope this helps, as I said I'll try to remember to post the .tgds later.
Inscrutable
