Fillet the conch meat on a cutting board to create flat 12 to 15 (1/4 to 1/2-inch) fillets - the thinner the better without breaking. Cover the pieces with plastic wrap and pound the meat with a mallet to flatten, doubling the width. Put the conch meat in a shallow dish and add the buttermilk and Cajun spice, tossing to make sure the conch is evenly coated. Let marinate, covered, in the refrigerator for 1 to 2 hours.
In a small bowl, combine the flour and salt and pepper, to taste. Remove the conch from the marinade, pat dry with a paper towel and dredge in seasoned flour.
In a large saute pan over medium-high heat, add 1 tablespoon grapeseed oil and when the oil is hot add the floured conch, cooking for 1 to 2 minutes on each side. Remove the conch to a plate and tent with foil to keep warm.
To the saute pan add the remaining grapeseed oil. Add the olives, garlic, tomatoes, capers and thyme, and cook over medium heat for 2 minutes. Remove the olive mixture from the pan and pour over the conch. Return the pan to medium heat. Add the wine to deglaze the pan, then add the stock, basil, lemon juice and parsley. Cook to reduce by 2/3 volume and swirl in the butter. Ladle into serving bowls and serve with warmed bread.