Put the sugar, honey, butter and orange zest in a large bowl and beat with an electric mixer until smooth. In a separate bowl sift together the flour, ground almonds, cocoa powder, spices, salt, baking powder and bicarbonate of soda, set aside.
Beat the eggs into the sugar mixture one at a time, whisking well after each addition then gradually mix in the flour mixture until well combined.
Cover the bowl and place in the fridge for half an hour (or overnight). Meanwhile, preheat the oven to 180C/350F/gas mark 4 and line two baking sheets with baking parchment.
Scoop out portions of the dough using a measuring spoon - about 1 1/2 tbsp at a time, and roll between slightly damp hands into smooth balls. Place them well spaced apart on the baking sheets and flatten them slightly with your fingers.
Bake for about 15 minutes until firm and lightly browned and a toothpick inserted into the centre comes out clean. Transfer the Lebkuchen to a wire rack and leave to cool completely.
Place the icing sugar in a small bowl and gradually mix in enough of the water to form a slightly runny icing - not too wet though or it will all run off. Place a wire rack on a baking sheet.
Dip the tops of the Lebkuchen in the glaze, allow the excess to drip off then place them right-side up on the wire rack to set.
Once the glaze has set, melt the chocolate, either in a bain marie or in short bursts in the microwave then pour it into a small bowl. Line a baking sheet with baking parchment. Dip the bottoms of the Lebkuchen in the chocolate, allow the excess to drip off then place them chocolate side down on the parchment to set. Once set store in an airtight container.