Cut the chicken breasts in half so you have 2 similar sized pieces that will fit in your bun and gently bash the thicker pieces to flatten. Mix the orange, peri peri, sugar and oil with some seasoning, then add the chicken and marinade for at least 15 minutes (30 if you can).
Heat a griddle pan or heavy frying pan until hot. Cook the chicken for 4-5 minutes each side until it’s cooked through.Add a slice of cheese to the top of the chicken and let it wilt a bit (or stick under the grill briefly).
Put some lettuce and a slice of red pepper on each bun and top with the chicken, some coleslaw and the bun lids.