Preheat oven to 200 / 180 fan forced. Place chicken in a large roasting pan. Arrange potato, onion, capsicum, garlic around chicken. Pour over stock. Fine grate 1 lemon. reserve grated lemon rind. Juice grated lemon. Cut remaining lemon into wedges. Add lemon juice and wedges to pan. Season with salt / pepper.
Roast 15 minutes or until chicken starts to brown. Reduce temp to 180 / 160 fan forced. Roast 25 minutes. Add tomatoes and roast 10-15 minutes or until chicken is cooked through and tomatoes are just starting to collapse.