First of all, a thankyou to enhzflep, gster123 and R@nSid for suggestions and advice regarding displacement mapping and so on. So here is the first stage of my latest work - which I've kept simple so I can learn a few tricks along the way (The spider I have had to put to one side since I am nowhere near experienced enough in texturing to battle that one for a while)

The colour texture is very rough (hence the strange line in the centre of the middle brick) - it's just there as a template so I know where all the bricks are, and all this so far is done with a very simple model and a displacement map which I did in Photoshop.