Preheat the oven to 180°C, Gas mark 4
Rub 2 tbsp of the olive oil over the outside of the chicken and then add then massage the sea salt flakes into the skin.
Place the chicken on the rack and pierce the chicken skin 5 times. Make sure that the chicken does not touch the bottom of the roasting dish.
Cook for 1 hour at 180°C, gas mark 4. Do not add any liquid.
Meanwhile, heat 2 tbsp of olive oil in a medium saucepan, brown the 4 peeled whole garlic cloves.
Add the white white, water, rosemary, butter and the zest of half a lemon. Bring to a boil and cook over a high heat for about 15 minutes so that the sauce is reduced slightly and the rosemary is infused.
Cut larger potatoes in halve or into quarters depending on their size.
Bring the potatoes to a boil in salted water. Boil for for 10 minutes, then drain, leave in cold water for a few minutes and then leave to drain.
Add the parboiled potatoes to the roasting tray, so that they are under the chicken.
After the 1 hour cooking time, pour the sauce over the chicken and potatoes. Cook for another hour (or until the chicken skin is golden and crisp).
Using kitchen scissors, halve the chicken. Salt the potatoes to taste and mix to coat the potatoes with the chicken juices and black bits!
Serve the chicken and potatoes with lemon wedges.