Place the chopped dates, bicarbonate of soda and boiling water into a bowl, mix well and allow to cool.
Line a 19x28cm (7½x11 inches) oblong tray with baking parchment.
Add the cake mix and vegetable oil to the cooled date mixture and mix well.
Add the pear cubes and mix well.
Pour the cake batter into the tin.
Bake in a preheated oven 190°C (375°F, Gas Mark 5) for 45-50 minutes until firm to the touch.
Leave in the tray to cool for 10 minutes before turning out to cool completely.
Mix the water with the icing sugar to form a thin smooth icing.
Pour the icing over the cooled ginger cake. Melt the chocolate over a bowl of simmering water and drizzle diagonally over the icing.