Soak cod in a bowlful of water for two days, changing the water every 12 hours. Remove cod from water.
Put fish into a pot with milk, onions, garlic, and bay leaves and bring to a slow boil on medium. Immediately reduce heat to medium low and simmer for 45 minutes. Let sit for 30 minutes. Strain milk from cod and onions and cool. Remove the bay leaves. Discard milk
While cod is cooking, gently bring potatoes to a boil in salted water and simmer until tender when pierced with a knife. Drain water from potatoes and peel while still hot. Mash them with a fork in a bowl until smooth. Set aside
Mash cod and onion mixture with a fork until everything breaks down; then add hot sauce, honey, Worcestershire, and egg. Add potatoes to cod mixture, and blend well. Fold in herbs and bread crumbs. Form mixture into round patties, cover, and refrigerate for 30 minutes or up to 24 hours.
Preheat oven to 350 F (180 C). Set a large, non-stick frying pan on medium high. Add grape seed oil and butter. When butter is melted, put cod cakes into pan in one layer. Fry for one to two minutes or until golden. Turn and fry for 2 more minutes until golden on other side. Arrange cakes in an ovenproof dish and place in oven for five to six minutes. Serve with tartar sauce.
As mixture thickens, dilute with vinegar; then oil may be added more rapidly. Add the olive oil after the grape seed oil in the same manner.
Keep refrigerated until ready to serve, then add remaining ingredients to finish.