Mash the anchovies with a fork and stir them into a bowl with the tapenade. Add the herbs, garlic and lemon rind, then pour in the wine and 4 tablespoons of the oil. Stir thoroughly, then rub the mixture into the lamb chops. Cover and leave at room temperature for about 1 hour.
Put the couscous into a heatproof bowl and stir in 2 tablespoons of the oil so that the grains are covered. Season with salt and pour over 400 ml (14 fl oz) boiling water. Leave to stand for 5–8 minutes until the grains are soft.
Season the lamb chops with pepper and cook them for about 2 minutes in a preheated hot griddle pan. Sprinkle with a little salt, then cook the other side for a further 2 minutes. Transfer to a warm dish, cover with foil and leave to rest for 5 minutes.
Fluff up the couscous with a fork and gently fold in the capers, olives and rocket. Sprinkle over the lemon juice, then heap the couscous on to warm plates. Arrange a lamb chop on each heap and spoon over the juices. Sprinkle with rocket leaves, drizzle with the remaining oil and an extra squeeze of lemon juice and serve immediately with lemon wedges.