Thanks Rick.
Geoff,
It's fairly easy, in short , paint the wall your base colour (in this case Tamiya Hull Red), then a thin wash of a light (not white) colour for the pointing. Let the light colour settle in the grooves, but don't worry about it setteling some on the brick work. This will be part of the final effect. Then use the base colour, and drybrush the wall, bringing the bricks out, but lightly. Vary the tone of your base coat by lightening and darkening your base coat. A brick wall is never one single shade of colour. Then using the same lighter and darker shades, and some contrasting reddish and brown colours, pick out individual bricks. Keep these random, swapping walls as you go along will help in that. Finish with a light dusting with pigments, to tie everything together. Again, vary the dusting, going a bit heavier along the bottom.
Study real walls for reference.
Hope that helps. I'm planning on picking up another one today, 'll do a SBS for an article with that.
Cheers
Henk