Mine snapped where the outer cable bends at the front of the wing/end of the bonnet.
Lift the edge of the bonnet then reach underneath for the outer cable, it sits on 2 plastic pegs. Yank it out, if you are a bit brutal the outer will slip away from the bonnet lock.
You then end up with enough inner cable (hopefully) to grab with plyers.
If you can't do that I'm afraid the worst case is smashing the grille in.