Place oil in a large roasting pan. Arrange chicken, chorizo, potato and onion in pan. Hit garlic with the flat side of a large knife to bruise and add to pan with lemon rind. Season well with salt and pepper. Toss to coat chicken in oil.
Cook for about 25 minutes. Add lemon juice and tomatoes and cook for a further 10 minutes or until golden and cooked through. Sprinkle with parsley to serve.