Preheat oven to 180 degrees C. Lightly grease a 20x30cm baking dish.
In a medium bowl, cream the white sugar and margarine together. Stir in the molasses and honey. Sift together the flour, bicarb soda, cinnamon, ginger and cloves; add to the creamed mixture and mix until well blended. Finally, stir in the raisins.
Press the batter evenly into the prepared baking pan. Bake for 20 to 30 minutes in the preheated oven, bars should turn golden brown. Top will appear smooth and dry to the touch.
Meanwhile, make the icing. In a smaller bowl, stir the icing sugar together with the milk and vanilla. Drizzle over the spice bars while they are still warm. Allow biscuits to cool before cutting.