Roast Chicken with Lemon and Bacon-Rosemary Roast Potatoes

4- to 4 1/2 lb. chicken

Sea salt and freshly ground black pepper

Yukon gold potatoes, peeled

large lemon

whole bulb of garlic, broken into cloves

sprigs of fresh thyme (or rosemary)

olive oil

fresh rosemary sprigs, leaves picked

slices of bacon, cut in half (optional)