This time I started with a spray of white primer and then gave the model a sepia wash. I then washed water on top of that to make the sepia collect more at the bottom of the walls to give me a graduated effect.
Then I decided to try a darker colour than the white I had used for dry brushing on the other models and choose Coat D'Arms Linen. I gave the model a heavy dry brush of the Linen to get the effect I wanted. I put most of the colour on near the top of the model and then brushed down to keep the graduated effect. This approach also picked out more of the surface detail on the model that had been lost on the other two models.
I was happy with this look as it gave me the rain washed look I was after with the dirt collecting at the bottom of the walls.
A light dry brush of white added some highlights and then I added the windows and doors.
I also decided to try a more redish colour for the exposed mud bricks which I'm fairly happy with but may revisit. Here are the three models for comparison.
Now I'm happy with the main colour scheme I'll move on to the larger 15mm buildings.