For the chakalaka relish: Heat the oil in a medium saucepan over medium heat. Add the onions and cook until softened, at least 5 minutes.
Add the red chiles, bell peppers, garlic, curry powder, mixed herbs and carrots, and cook for another 3 to 5 minutes.
Add the beans, tomatoes, chutney, ketchup and a generous pinch of salt and pepper. Bring to a simmer and cook for 30 minutes.
For the BBQ chicken: In a jug, mix together the ketchup, olive oil, balsamic, honey, lemon juice, paprika, cilantro, cinnamon, garlic, chiles and a generous pinch of salt and pepper.
Brush the chicken with some of the sauce, cover with plastic and refrigerate at least 1 hour, or preferably overnight.
Remove the chicken from the refrigerator 20 minutes before cooking to bring to room temperature.
Grill the chicken, lid down, for 30 to 35 minutes, or until cooked through, turning halfway and basting with extra sauce every 10 minutes.
Serve immediately with a side salad or a generous spoonful of mealie pap or polenta and the chakalaka relish on the side.
To turn a whole chicken into a flattie (i.e., to spatchcock), place the chicken so that the drumsticks are on top, and cut along the breastbone with a kitchen scissors. Pull the chicken apart and lay it flat on a roasting tray.