Preheat oven to 425 degrees F.
Rinse the chicken with cool water, inside and out. Pat it dry with paper towels. Divide the herbs, keeping 1/2 of them whole. Finely chop the other half. In a small bowl, mash the softened butter with the chopped herbs, until combined. Rub the herbed butter under the skin, as well as all over the outside of the chicken. Season the bird all over with salt and pepper. Stuff the cavity with the orange, garlic, 1 onion, and the remaining herbs. Tie the legs together with kitchen twine to help hold its shape. Place the chicken, breast-side up, in a roasting pan. Put the remaining onion into the pan, which will help color and flavor the sauce. Lay the strips of bacon across the breast of the chicken and roast for 25 minutes.
Remove the bacon and baste the chicken with the drippings and cook for another 25 minutes to brown the skin. The chicken is done when an instant-read thermometer reads 165 degrees F when inserted into the thickest part of the thigh (the legs of the chicken should wiggle easily from the sockets too.) Remove the chicken to a platter and let stand for 10 minutes, so the juices settle back into the meat before carving.
Meanwhile, remove the softened onion from the roasting pan. Tilt the pan so the drippings collect in 1 corner, skimming off as much fat as possible, and leaving the drippings. Place the roasting pan on top of the stove over medium heat and take a wooden spoon to scrape up the flavor from the bottom of the pan. Stir the flour into the drippings to make a roux-like paste. Pour in the chicken broth in stages; continue to stir to dissolve the flour evenly to prevent lumps. Stir in the sherry and season with salt and pepper.
To serve, carve the chicken tableside and squeeze the oranges from the cavity over the meat.
Serving suggestion: roast potatoes, watercress and gravy.