In reply to Ramblin dave:
Theeasiest way I found with those types of brakes was
Firstly check that the wheel was true to within about 1mm wobble.
Second, undo the bolts on both sides, and then wind the brake adjustment screw on the levers out as far as they can go whilst still on the thread
Third, get a piece of card about 1mm thick to wedge under one end of each block to allow for toe-in.
Fourth, hold the pads against the rim (and card) making sure that the shaft/bolts on the pads are perpendicular to the rim
Fifth, whilst still holding the pads as hard as you can, tighten the bolts for the pads to a reasonable tightness on each side, then use an allen key in one side to counter the movement of the spanner on the other while you fully tighten each pad
Sixth, pull out the card, and wind in the adjustment bolts on the levers until the pads are clear of the rim so the wheel can rotate without rubbing.
Takes about 5 minutes per set and is pretty easy to get right - just remember to make sure the pads are vertically central on the rim surface so they don't rub the tyre or risk slipping off the rim towards the spokes.