stuart 45,
An interesting suggestion (pattress plates--here they're called rock bolts or soil nails, depending on the application), but I suspect problems associated with drilling through the parapet walls (from the roof side, for ease of access) to install them, without doing considerable damage to the already precarious facade, would rule out such a plan. Drilling would have to be precise, passing through mortar joints only, to minimize the chance of dislodging any bricks. Furthermore, it's likely the vibrations resulting from rotary percussion drills would further loosen the brickwork.
I recall seeing quite a few older brick and stone facade buildings in Europe (Amsterdam comes to mind) during my visits there, having pattress plates on the exterior side. Meaning that such methods are certainly possible to implement, provided proper skills and experience are used, and adequate precautions are taken (suspended work platforms or scaffolding, netting or hardcover shelters to protect street traffic from falling debris, etc.).
Possibly a more realistic solution might be to have custom, inverted U-shaped frames fabricated and installed. Spaced at uniform intervals, they would have bearing faces against the brick on the street side, and could have simple screw-type mechanisms to be manually activated from the roof side, in unison, to uniformly draw the brick facade back to the wall face. Once things were drawn up to correct position, the screw mechanisms could be locked and short retainer anchors installed on the roof side, with no drilling needed on the street side.
