Melt honey, butter and brown sugar in a pan over a low heat. When sugar has dissolved, turn up heat and boil for 1 minute then turn off heat & leave to cool for 10-15 minutes.
Preheat oven to 160°C. Line a 2lb loaf tin with baking parchment.
Beat the eggs and add into the saucepan with the butter/sugar mix.
Add the mixed spice to the flour in a large bowl and pour in the butter mixture. Add the sultanas, mix well, then pour the batter into the lined tin.
Bake for 50-60 minutes or until a skewer inserted into the centre of the cake comes out clean.
Leave cake to cool for a few minutes in the tin, then take out and leave to cool on a wire rack.
For the icing, add enough cold water to the icing sugar to create an icing with a runny consistency. Drizzle over the cooled cake.
Serve in slices spread with butter, if you like. This cake tastes even better the next day when the flavours have developed.