Blender mirror problem in unity

To separate the two parts, head back into blender, tab into edit mode, press alt + z and then select the part to be separated, then you can either right click or select separate or just press p.....choose selected from the menu and then the object should be separated, this solution is followed by another problem relating to the transform...if you just want to place the object as an non interactable object, this is fine but if you want to change it's position, rotation or scale.....it can be a grave problem.....the solution to this problem has been answered here....transform problem