Mix all the ingredients for the peri-peri sauce together in a jar or bottle with a lid. Shake it well and leave to stand for at least a day before using.
Cut through the flesh of the cleaned, de-veined prawns to butterfly them.
Mix the oil and garlic together and pour over the prawns. Leave to marinate for one hour.
Grill over hot coals on the braai. Cook only for about 45 seconds a side.
Place the hot chips on a platter. Remove the prawns from the pan and place onto the chips.
Drizzle liberally with the peri-peri sauce, or serve the sauce on the side if you prefer. Serve immediately with lemon wedges.