1) Preheat the oven to 190C/Gas 5.
2) Heat the oil in a large saute pan over medium-high heat. Season the chicken with salt and pepper and sear in the pan, only to brown the skin not to cook through. Remove the chicken.
3) Add the onions to the pan and cook until tender, about 5 minutes, then add the garlic and cook until fragrant. Add the chilli sauce, sultanas and sugar.
4) Return the chicken to the skillet, skin side up, and cover the pan tightly with aluminium foil. Bake in the oven for 1 hour 15 minutes. Uncover the pan, add the sherry, water and fruit, and bake for another 20 minutes.