Preheat the oven to 180°C / 350°F / Gas mark 4.
Mix the chicken and garlic with 1 tablespoon of oil in a shallow roasting tin, then poke around a few bay leaves. Season with salt and pepper then roast for 30 minutes.
After 30 minutes, fish out the garlic, increase the oven temperature to 200°C / 400°F / Gas mark 6.
Roast the chicken for 15-20 minutes further until golden, crispy and cooked through.
Bring a large pot of water to the boil and cook the potatoes until a fork eases through.
Mash well with butter and 3 tablespoons or more if needed of milk.
Squeeze the roasted garlic cloves out of their skins and mix into the mash. Cover and set aside.
Pulse the olives in a food processor to roughly chop, then scrape into a serving bowl.
Add the flat-leaf parsley, chillies, orange zest, orange juice, lemon juice, remaining olive oil and some seasoning.
Set aside at room temperature until ready to serve.
Serve the roast chicken, olive salsa dressed with the juice of the remaining half lemon along with the garlic mash.