In a small bowl mix together lime juice, oil, chillies, coriander/cilantro and pour over fresh cod, let it marinade for 15 minutes.
If you are using the corn, preheat the grill and cook the corn for 15 minutes, turning frequently until charred and cooked through. Set aside to cool. When cooled enough to handle, cut the corn off the cob with a sharp knife.
Slice the red cabbage very thinly, if you have a mandoline, use it, then toss the sliced red cabbage with lime juice, white whine vinegar and salt. It will immediately start to change colour from purple to pink. Set aside.
Prepare the salsa but gently combining blackberries, green chillies, lime juice and salt. Set aside.
Preheat the oven to 400F/200C, place the cod in a shallow baking pan and cook for 15-20 minutes until the fish flakes easily with a fork.
Assemble the tacos by filling them with bits of fish, red cabbage slaw, blackberry chilli lime salsa and charred corn according to taste.