Bring a large saucepan of salted water to the boil and par-boil the potatoes for 12-15 minutes until just tender. Drain and allow to cool for a few minutes.
Preheat the oven to 200°C.
Place the breadcrumbs, herbs and seasoning in a food processor and pulse until combined. Melt the butter in a small saucepan, then transfer to a large mixing bowl. Add the breadcrumb mixture and the egg and mix well to bind thoroughly. Carefully loosen the skin around the legs of the chicken and push some of the stuffing into the created space, distributing it evenly. Stuff the main cavity of the chicken with the rest of the stuffing - making sure it isn't packed too tightly, so that it cooks through.
Sit the chicken in a roasting tray and rub the olive oil all over. Season well and roast in the oven for 30 minutes. Remove from the oven. Pour the sunflower oil into another roasting tray and place in the oven on the top shelf for 10 minutes to get hot.
Return the chicken at the same time onto the bottom shelf and continue to cook for 60-70 minutes. Remove the roasting tray with the sunflower oil in it after 10 minutes and carefully place the parboiled potatoes in the hot oil.
Season them and shake around the pan carefully to coat in the hot oil then return to the oven for 60-70 minutes until golden and crispy. Remove the chicken when it is cooked and the juices run clear when a skewer is inserted. Keep warm wrapped loosely in aluminium foil. Remove the potatoes once they are cooked and ready. Lift the chicken onto the roast potatoes in their tray and serve.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.