banjo bolt Ive seen already has a hole through it. Did it break off low enough to get to the hole in the bolt? If so an easy out (or bolt extractor) is the way to go. It is agressively reverse threaded so it tightens into the bolt counterclockwise and tries to break the blot shaft loose. Of course, there shouldnt be much resistance to the bolt shaft coming back out anyway as I assume it was recently loose and not seized in place.
On a side note, invest in a torque wrench.