Get grilling and make the most of a sunny day with this easy-to-prepare chicken dish that is full of flavour. Mix together the oil, garlic, lemon zest and juice, rosemary, vinegar and chilli in a medium bowl. Add the chicken and toss to coat. Season well to taste. Cover and leave in the fridge to marinate for at least 1 hour, or overnight. When ready to barbecue, cook the chicken on a gas or charcoal grill for 30-40 minutes over a very low heat, turning often, until charred. Cut into a thick chunk and check that it is cooked through, with no pink showing. Add the lemon slices and quartered garlic cloves and chargrill for the last 10 minutes. Serve the chicken with the grilled lemon slices on a large platter. Tip: You can partially cook the chicken in the oven for 20 minutes at gas 6, 200?C, fan 180?C before grilling to help it along. If using a gas grill, turn off the middle burners and keep the heat low. For a charcoal grill, place a foil-lined tray underneath where the chicken will cook and push the coals around the side.