On the left hand side, the main wiring loom continues its route to the headlamp cowl in the form of the front sub-harness - it is cable tied to one of the fairing stays which extends forward from below the top line of the fairing pocket towards the front. The cable is held under the spar. As SupraSabre said, there is a shrouded cluster of wires and connectors that sits in a moulding on the outside of the left fairing pocket.
The dark grey inner cowl, which is attached to the inside lip of the fairing pocket by two plastic push rivets (turn the bars to the right, and you can see them in the space left by the fork leg) - sits on one side of the fairing stay. The fairing pocket sits on the other side. There is just enough room to get the OEM sub harness through the space. (That fairing stay and cable is a little under where the edge of the fairing pocket sits, on the side with the key hole).
My first attempt to route my own harness had it strapped to the same fairing stay. When I put the fairing back on, the new wiring was too bulky and pressed the inner cowl into the path of the fork leg. My only other option was to sling it underneath the OEM front sub harness. IIRC, the cable ties are physically attached to the underside of the stay, so that the sub harness is guaranteed to sit underneath the stay.
Short answer - there isn't much room, but there is a cable, and it is possible to add another underneath.
