Preheat the oven to gas 7, 220°C, fan 200°C. Boil the potatoes for 5 mins, then drain well. Transfer to a shallow roasting tin and add the courgette and red onion.

In a jug, mix 1 tbsp oil with half the lemon juice and zest. Pour over the veg in the tin, tossing to coat. Roast for 15 mins, then stir in the lemon wedges and olives and roast for 15-20 mins until the veg is tender and golden.

Meanwhile, sprinkle the remaining zest over the fish and season with black pepper. About 5 mins before the veg is ready, heat a large nonstick frying pan over a high heat until very hot. Add ½ tbsp oil and swirl the pan to coat. Add the fish, skin-side down, and fry over a medium heat for 1-2 mins or until the skin is crisp and golden. Flip and fry for 1-2 mins until just cooked through and the fish flakes easily.

Divide the roasted veg between 2 plates, top with the fish and drizzle over the remaining lemon juice. Serve garnished with the parsley and extra black pepper.