Melt the butter and allow to cool slightly. In a microwave-safe bowl, pour milk and water and heat until warm, about 30-45 seconds.
Add honey to this and mix well. In a large bowl add wheat flour, all-purpose flour, oats, yeast and mix well.
Add butter, milk-water-honey mixture and salt to the flour mixture. Mix the dough using a wooden spoon.
Transfer the dough to a lightly floured surface. Lightly flour your hands and knead until dough is smooth, elastic and slightly sticky, about 10-15 minutes.
Keep the dough in a lightly oiled bowl and cover with a tea towel. Let the dough rise for 1 hour or until doubled.
Once the dough is doubled, punch down and transfer to a lightly floured surface. Flatten the dough into a 8 x 8-inch square.
Tightly roll the dough into a log, tucking in the sides. Place the dough, seam side down, in a lightly greased or parchment lined 9 x 5-inch loaf pan.
Cover with a tea towel and let the dough rise until it reaches the edges of the pan (not doubled), about 20-30 minutes.
Preheat the oven to 190 °C | 375 °F. Brush the top lightly with milk and sprinkle oats.
Bake for 40-50 minutes, rotating halfway through baking, until loaf is deep brown and sounds hollow when tapped on the bottom.
Let the loaf cool on the wire rack for 5 min, then remove from loaf pan, place on cooking rack and allow to cool completely.