This is how they looked when they arrived:
They're cast in a creamy-white resin/plastic which holds the fine detail very nicely. First job was to spray undercoat the lot in chaos black.
Then I painted the earthy bits in burnt umber.
Next I went over all the walling with a light grey, thinned down to let the black show through a bit in patches.
Then went over liberally with a black ink wash to well into the cracks and crevices.
Finally, to finish off the walls, I faintly drybrushed with a bone white. This really pulls out the edge, and set against the ink wash finishes off the slate effect very well.
For ground detailing, I painted on thin lines of pva glue into some of the cracks and added some mossy scatter.
I have still to add the grass over the top to complete the pieces, (pics at a later date.)
I think the (almost!) finished result is very realistic and will be a great addition to my scenery pieces for Lord of the Rings wargaming.