Heat the oven to 200C/fan 180C/gas 6. Put the sausages, potatoes, chickpeas, peppers, corn slices and onion in a large baking tray. Combine the olive oil, garlic, lemon juice and spices in a small bowl, seasoning well. Pour the oil mixture over the vegetables and toss to coat. Cover securely with foil and roast for 30 minutes.
Uncover the tray and roast for a further 30 minutes or until the sausages are cooked through, the potatoes are tender and everything is golden. Serve sprinkled with the parsley and lemon wedges to squeeze over.