Lay the mackerel fillets on a plate. Mix the piri piri marinade ingredients together and brush over both sides of the fish. Leave to marinade for 30 minutes.
Preheat the grill until it is glowing red. Arrange the mackerel fillets, skin side uppermost on a baking sheet and spoon over any remaining marinade
Grill the fillets for 4 – 5 minutes on the skin side only until the flesh has lost its translucency and the skin has blistered and peels away easily.
Arrange on a large serving dish and sprinkle with chopped parsley and lemon juice. Arrange the lemon wedges around the edge. Serve with bread or potatoes.