I should have known it would be you to the rescue! Many, many thanks!

Since I can't remember which atmos I used (it's either a vue6 atmos used as-is, or slightly tweaked), I'll send you the scene. (Don't worry, I'll remove the mat from the ground so there will be no copyright issues)!

In the meantime, I'm going to test your tips & check out the pdf file. (Btw, I'm pretty sure it was your tips I had read before! The bit about the quality slider in the atmosphere settings sounds verrrry familiar!)

Thanks again!