Melt the butter with the oil in a flameproof casserole and gently fry the onion and chorizo for 5 minutes until beginning to brown.
Add the quails to the pan and fry in the oil mixture, turning frequently, until seared on all sides and beginning to colour. Drain the quails to a plate.
Add the peppers and fry for 5 minutes, turning them in the oil mixture. Stir in the tomato paste. Return the quails to the pan and brush with the honey. Pour the sherry over and season with salt and pepper.
Cover with a lid and transfer to a preheated oven, 180°C (350°F), Gas Mark 4, for 30 minutes until the quails are cooked through. Test by piercing a thick area of flesh with the tip of a sharp knife; it should feel very tender. Check the seasoning and transfer the pepper sauce to serving plates. Place the quails on top and spoon any cooking juices over them.