But any idea of what is happening here. I am rendering using open GL with a sun light however the shadows produced are cut off at a certain point. I am well aware that this can be fixed with a shadow map however I would like to know if this is merely a program limitation or I am doing something completely wrong.
This is intentional, the fact that the sunlamp shadows use a traditional shadowmap as opposed to techniques like SPPM means that a frustum has to be defined around the position of the sunlamp (so as to allow for shadows that are not blurred into oblivion due to resolution limits).
Right now, you would need to do a combination of increasing the frustum size and increasing the shadowmap resolution.