Prepare honey mustard dressing: in a medium-sized bowl, combine honey, Dijon, vinegar and mayonnaise and whisk until smooth. In a separate bowl, toss cabbage with a few tablespoons of honey mustard dressing and set aside. Slice scone loaf in half, through the center. Scoop out some of the center of the loaf to create a shallow crater to better accommodate the filling. Spread each half with honey mustard dressing. Place cabbage on bottom half of scone; top with corned beef. Sandwich with the top half of the scone and slice into 3 or 4 servings.