Position rack in lower third of oven. Preheat oven to 425°F/220 °C. Have ready a large roasting pan and rack; set aside.
Remove turkey neck and any giblets from turkey orifices; set aside. Pat turkey dry inside and out. Season turkey inside and out with 1 tablespoon salt and the pepper.
Stir together the softened butter, remaining salt and FODY Lemon & Herb Seasoning in a small bowl. Zest the lemon and orange right over the bowl and stir the zest into the butter mixture.
Very carefully loosen the turkey skin starting at the neck cavity by sliding your fingers between the skin and the flesh, taking care not to tear the skin. Rub the seasoned butter all over the breast between the skin and flesh, then rub any extra seasoned butter all over the outside of the bird.
Quarter the lemon and the orange. Stuff about one-quarter of the chopped leeks, 1 lemon quarter and 1 orange quarter into the neck cavity. Stuff the remaining citrus and leek greens in the main cavity. Tie the legs with Butcher’s twine and place bird in roasting rack; tuck wings underneath the turkey. Also make sure neck skin is tucked neatly beneath the bird. Pour water in bottom of pan.
Place bird in oven and roast for 30 minutes. Turn bird around, decrease temperature to 350°F/180°C and roast for another 30 minutes. Rotate bird again, this time basting with pan juice. Keep rotating bird for even browning every thirty minutes, basting each time, until an instant read thermometer reads 165°F/74°C when inserted in the thickest part of the thigh (not touching the bone). If at any time the bird gets too brown, simply cover loosely with aluminum foil. Total roasting time will be 2 1/2 to 3 hours.
Remove turkey from oven, remove contents of main cavity then tilt the turkey to drain any juices into pan. (You can remove the neck cavity contents when you carve). Rest turkey on cutting board for at least 20 minutes to allow juices to redistribute before carving. Cover loosely with aluminum foil. Meanwhile, use pan drippings to make your gravy. Carve and serve!