Still very basic, but I at least managed to fix the algorithm so it generates the fractal landscape correctly. I am now looking into shadows, which are looking to be slightly trickier than I had previously imagined. Once shadows are added the landscape will look a lot more realistic. Instead of plain flat colours. I will also add sky at some point which can be generated from the same technique as the landscape.

Heres the link:
http://cis.strath.ac.uk/~chodgins/frac1.gif