To prepare dough: Place sifted flours, wholemeal flour, bread improver, milk powder, sugar, salt, and yeast into the bowl of an electric mixer fitted with a dough hook. Mix for 20-30 seconds.
Pour in the coffee mixture and continue to beat for 5-6 minutes. Add the butter and mix to a smooth dough. Leave to rise for 40-45 minutes, until doubled.
Knock back the dough and knead until smooth.
To shape: On a lightly floured surface, roll the dough out to a rectangular shape. Scatter the walnuts and raisins over the dough.
Roll up the dough and cut into three equal portions. For each portion, close the ends well and place all three into a greased and floured loaf pan. Cover with a damp tea towel. Leave to rise until doubled in size.
To bake: Preheat the oven at 200°C. Lightly brush the top of the loaf with milk and sprinkle some oats over. Bake for 25-30 minutes, or until golden brown. Remove from the oven and cool on a wire rack.