Put the couscous in a bowl and pour over 300ml of boiling water. Cover with a plate and leave to do its thing.
Put a griddle pan on a high heat to get nice and hot. Once it’s ready, rub a tiny bit of oil into the sardines and add them to the pan. Sprinkle over a little salt and cook for about 5 minutes.
Meanwhile, mix the harissa in a small bowl with a lug of extra virgin olive oil and the juice of a lemon. Turn your sardines over in the pan then brush them lightly with the harissa sauce. Pop a lemon half, cut-side down, at the side of the griddle pan.
Squash the olives with the heel of your hand, pull out and discard the stones then finely chop the flesh. Fluff up your couscous with a fork then add the spring onions, olives, mint and feta. Add a good lug of extra virgin olive oil and the juice of your remaining lemon half. Gently mix it all together then have a taste to check the balance of flavours.
To check your fish is cooked go to the thickest part of the flesh and it should pinch away easily, you’ll also be able to cleanly pull the bone away. Pile the couscous on a board or on your plates and top with the sardines. Dollop a bit of yoghurt on the side topped with some of that fiery harissa sauce. Pop the rocket on the side, squeeze a little of the caramelised lemon over each portion and tuck in.