Sketch is complete! Didn't take very long as I'm currently attempting to speed up my workflow and care less to small fine detail that the human eye doesn't normally notice.
I am very happy with the sketch as I was able to do it quickly whilst maintaining some form of standard throughout. Unfortunately the shotgun isn't exactly straight nor do the lines of text quite follow the curvature of the robot's main body.
Next step is then to begin creating the actual 3D model which hopefully will turn out even better than this (sorta?) did.