Preheat the oven to 180 degrees C.
For the spatchcock, cut each butterflied bird in half down the middle and brush well with 2 tablespoons of olive oil. Season and set aside until required.
For the beetroot, place the prepared beetroot into aluminium foil and drizzle over 2 tablespoons of olive oil and season lightly. Seal the foil making a "pouch" and place into the preheated oven for 30 to 35 minutes or until the beetroot are just soft. Remove from the heat, unwrap, place into a large ceramic bowl and allow to cool.
Meanwhile, preheat your BBQ or chargrill. When hot, baste the spatchcock again with the oil and seasoning and place them onto the BBQ. Cook for 8 to 10 minutes, baste again and then turn and cook for a further 8 to 10 minutes on the other side or until cooked to your liking. Set aside in a warm place until required.
For the salad, place the oranges, watercress, baby herbs and spring onion into the bowl with the beetroots. Drizzle over the orange juice and olive oil, season lightly and then mix gently to combine.
To serve, place some of the beetroot and orange salad into the middle of four plates and top with half a spatchcock. Drizzle over a little of the dressing and serve immediately.