OK, seeing as I cant seem to edit my post...
I bought some new wood - mopani wood which is much more interesting, so i may not use the cork at all. I have also decided seeing as it is my first tank, to use the exo-terra backdrop with some modifications to reduce the risk of failure :|
I've already siliconed the polystyrene in place in the back of the tank to prevent the fruit flies from getting behind, and to help hide the back I've bought a weeping fig and a prayer plant, both fairly large.
Will update with photos when I get some better light.