Preheat oven to 220℃ (200℃ fan forced). Line a deep baking tray or dish with baking paper. Remove chicken from packaging and pat dry with paper towel. Place chicken into baking dish.
Using the cut side of the lemon halves, rub and massage the chicken all over making sure to release the juices. (make sure to really rub it in firmly). Place the lemon halves into the cavity of the chicken then drizzle with the olive oil and rub over gently to coat evenly. Turn chicken breast side down in pan. Set aside.
Combine remaining ingredients in a small bowl to make the spice mixture.
Using one-third of the spice mixture, sprinkle (from a height) the mixture over the bottom of the chicken to coat evenly. Carefully turn the chicken breast side up. Starting around the nook and crannies around the legs and wings, sprinkle with the seasoning mixture then sprinkle generously all over to coat the top and sides. Be careful not to touch the skin with your hands as it will disturb the coating. We want a nice even cover.
Once coated, using olive oil spray, spray the chicken so the coating is just moistened with oil. Transfer to the oven and roast for 1 hour and 20-30 minutes, basting half way through cooking time, until juices run clear when chicken thigh (in the thickest part) is pierced with a skewer. (Internal temperature needs to be at least 75℃ (165℉).
Remove chicken from oven and baste once again with juices. Set aside for 10 minutes to rest before carving or cutting into serving size pieces. Serve chicken with your choice of sides.