Bring the stock and water just to the boil in a saucepan. Reduce heat to low and hold at a gentle simmer. Heat the oil in a saucepan over medium heat. Add the onion and cook, stirring occasionally, for 5 minutes or until soft. Add the garlic and cook, stirring for 1 minute.

Place the barley in a bowl. Cover with water. Set aside overnight to soak. Drain.

Stir in the barley and lemon rind. Add the wine and stir until reduced by half.

Add a ladleful (about 125ml / 1/2 cup) of the simmering stock and stir constantly until the liquid is completely absorbed. Continue to add stock, a ladleful at a time, stirring constantly and allowing the liquid to be absorbed before adding the next ladleful, for 20-25 minutes or until barley is tender. Remove from heat. Stir in the lemon juice, rocket and parmesan. Cover and set aside for 5 minutes.

Meanwhile, heat a chargrill on medium-high. Lightly brush both sides of the chicken with oil. Cook on grill for 5 minutes each side or until cooked through. Transfer to a plate and cover with foil. Set aside for 5 minutes to rest. Thinly slice diagonally across the grain.

Divide the barley mixture among serving plates. Top with chicken. Season with pepper. Serve with lemon wedges.