Rinse the chicken and pat dry. Place the chicken in a heavy bag and set in a large bowl.
In a small pot, heat the olive oil over low heat. Add the whole crushed garlic cloves to the oil and cook for 5 minutes. Remove from the heat and let the oil stand until cool.
Remove the garlic from the cooled oil and discard. Combine the oil, paprika, piri-piri sauce, lemon juice, garlic powder and the salt and pepper. Pour over the chicken, turning to coat, then close bag and refrigerate overnight, turning several times. Let stand at room temperature for 1 hour prior to cooking.
Preheat the oven to 350°F Remove the chicken from the marinade. Lay the carrots in the roasting pan then place the chicken on top of the carrots. Pour the marinade over the chicken then add the water to the pan. Bake in the oven, basting regularly for approximately 120 - 180 minutes, or until a meat thermometer registers 180°F (add a bit more water if sauce gets dry). Add the potatoes to the roasting pan after the chicken has been in the oven for 1/2 an hour. Taste the potatoes for salt and adjust to suit your taste. I like my sauce nice and red, so will usually add extra paprika while it's cooking.
Remove the chicken from the oven and let rest for 5 minutes. Strain the marinade from the pan and serve with the chicken.
***Alternatively, the chicken can be placed on a rotisserie rod with a drip pan placed below and slightly in front of the bird to catch any drippings and prevent flare-ups as the bird rotates. Add the remaining marinade and water to the drip pan. Grill the chicken on a medium-high setting, brushing often with the marinade. Barbeque for approximately 120 minutes, or until the meat thermometer registers 180°F I have also cut up the chicken prior to marinating it, then barbequed it low and slow on the grill -- delicious.***.