Preheat the oven to 180ºC (fan 160ºC/350ºF/Gas 4). Grease the loaf tin and line with baking parchment. Mash the bananas. Put the butter, muscovado sugar, eggs, flour, baking powder, and milk in a large bowl and beat using an electric hand whisk for 1 minute (or 2 minutes with a wooden spoon) until blended. Add the banana and beat for 30 seconds or until mixed in. Stir in the chopped pecans. Spoon the mixture into the prepared tin. Level the top. Bake for about 1 hour or until well risen and golden brown. Check after 45 minutes. If the top is browning too much, lay a piece of foil over it. To see if the loaf is done, insert a fine skewer in the middle; it should come out clean. Leave the loaf to cool in the tin for a few minutes. Run a palette knife around the edge of the tin, turn out the loaf, peel off the lining paper, and finish cooling on a wire rack. When the banana loaf is cold, sift the icing sugar into a bowl and stir in the honey and 1⁄2 teaspoon of cold water to make a runny icing. Drizzle this over the cake and lay the pecan halves down the middle.