Please do let who knowjust in case someone else had the same issue be nice to find out what it was.
Ok ok
Let me start by saying the issue with my old mouse (cm sentinel) is a disconnect issue related to windows 8.1, I've had this confirmed by cm.
So now my g500s was giving me no control using infantry...last night I let go of the mouse and noticed the camera was slightly moving in one direction, so unplugged my 360 controller and boom mouse is back in action.
360 controller is about 8 years old and worn, the right thumb stick has a lean on it which is occasionally sending movement commands to bf4, overriding mouse input.
Tl;Dr I need a new 360 controller.