Mix together the honey, 1 teaspoon salt, mustard and soy sauce in a small bowl. Place the chicken on the lower rack of the halogen oven and spread the honey mixture over it. Pour the stock into the bowl of the oven.
Set the temperature to 200°C (392°F) and cook the chicken for 1 hour, turning it after 20 minutes' cooking time, then back again after another 20 minutes. Check that the meat is cooked through by piercing the thickest area of the thigh with a knife; the juices should run clear. Cook for a little longer if needed. Leave the chicken to rest in a warm place while you finish preparing the sauce.
Add the wine to the bowl with the stock. Increase the temperature to 250°C (482°F) and cook for 6–8 minutes until the juices are bubbling. Stir in the grapes and cook for a further 2 minutes until hot.
Pour the sauce into a warm serving jug and stir in the yogurt. Season to taste with salt and pepper, and spoon a little over the chicken. Serve the chicken with the remaining sauce, buttered new potatoes and mangetout or sugarsnap peas.