I'll have to get the camera out to illustrate just how futile it seems to try and get a bolt of any kind in there. I can
just barely see the hole, let alone manoeuvre a fitting in. Add to that, the arm is very, very close to the bolt head (to the point I had to lever the arm out of the way so the bolt would turn when removing it) so I can't see how any sort of socket fitting is going to work.
Right now, I've left the bracket bolted up tight with three of four bolts. I can
only just get visible movement in the bracket with screwdriver leverage, but any movement there at all is going to result in variable toe angle under load and therefore bum-steer. I just don't see how I can get anything in that hole without grinding the fold-over off the bracket...
(btw, your link goes to 'Rally of Canberra'.. I assume that's not what you intended?

I'm really interested in how you got a fitting in there...)