Thanks Captain Richards!
Used your tutorial to blatantly copy your brilliant work mate. Here is my humble efforts on an 18th century house:
(http://2.bp.blogspot.com/-DgvnXQWp-pk/U7I_RK1XnEI/AAAAAAAAB5c/YmPVdD3pMAE/s1600/104_3165.JPG)
Thank you so much - you have really opened my eyes to the possibilities of this method.
A few more pics on the blog:
http://adventuresinlead.blogspot.com.au/2014/07/houses-for-18th-century-horror.html