Corned Beef Fritters with Dipping Sauce

Name: Corned Beef Fritters with Dipping Sauce
Ingredients: 1 cup mayo; 6 Tbs. ketchup; 2-3 tsp. prepared horseradish, or to taste; Drizzle of Worcestershire sauce; 4 cups mashed potatoes; 2 cups finely chopped cooked corned beef; 1 cup shredded Swiss cheese; 1/2 cup grated Parmesan cheese; 2 cups sauerkraut, very well drained (my favorite sauerkraut is from Hoganville Family Farms!); 1/2 tsp. granulated onion; 3-4 scallions, minced, green parts only; 2 eggs, beaten; 2-3 Tbs. water; 2 cups panko crumbs; 1/2 cup vegetable oil, for trying fritters