Reserve 2 tsp oats for the top of the loaf then mix the rest with the yoghurt and honey. Set aside for 15 minutes to soften.
Meanwhile, mix together the flours, salt and yeast in a large bowl. Make a well in the middle, add the water and the oil, then add the oat and yoghurt mixture.
Bring the dough together using your hands, then turn out and knead for 15 minutes using the push and pull technique (use the heel of your hand to stretch the dough away from you, then fold it back on itself. Make a quarter turn then repeat and continue until smooth and springy.
Stretch the dough out into a rough rectangle and, saving 2tsp seeds for the top, sprinkle the walnuts, seeds and dried fruit over the dough and knead it gently until well incorporated and evenly distributed.
Reshape the dough into a neat oblong and place onto a lined baking tray.
Using a serrated knife, gently make a shallow slash down the centre of the loaf, brush with milk and scatter on the reserved oats and seeds. Cover with oiled cling film and leave to rise in a warm place for at least 1hour 30 minutes.
Heat the oven to 200°C, 180°C fan, gas mark 6. Bake for 35-40 minutes until risen and golden - the loaf should sound hollow when tapped on the bottom.