To adjust the handbrake you need to carefully pull up the leather gaiter by the rear of the base base and pull out of the way it turn until it's inside out. Put the car in 5th gear and slowly release the handbrake. Undo the top locking nut and adjust the handbrake travel by tightening or loosening the lower bolts i.e. tightening makes the travel shorter.

    The handbrake is adjusted correctly when it takes between 5 and 10 clicks to be fully on, you can check both rear brakes are equally adjusted by slowly rolling the car forwards and stopping it on the handbrake, if you feel it rocks the car, the side that rises first is this side that is braking more than the other so either loosen it off a bit or tighten up the other side, don't rely on looking at the two threads and adjusting each one until they are equal as this doesn't take into account cable stretch and differing pad wear etc - this can clearly be seen in the picture.

One they are adjusted equally tighten the top locking bolts and clip the handbrake leather gating back into place.