For some final touches I decided to extrude a few more sections to complete the shape and match it to images online. This concluded with pulling out the gun segments and this took a few attempts to get correct, I found the best way was to move the vertex's separately. This can't have been the best way because it was freehand but I matched them up using the front view. Next I added a few bevelled cylinders for the two back lights and the two guns to the front. I then had a tidy up by removing a few more edges to clean the shape up.
After this I mirrored the wing and this completed the entire tie fighter. Looking at the complete model I am very pleased with it, I think this turned out better than the sandcrawler but this could partially be because so much of the sandcrawler needs to be textured to make up for the vast parts un-detailed segments.