Pre-heat oven to 200°C/400°F/gas 6.
Scald the milk. Remove from heat and stir in the butter, brown sugar and salt. Leave aside until lukewarm.
Combine the yeast and warm water in a large bowl and leave until the yeast has dissolved and the mixture is frothy. Stir in the milk mixture. Add the flour and 10oz (285g) of the porridge oats and to obtain a soft dough. Transfer to a floured surface and knead until smooth and elastic. Place in a greased bowl, cover with a plastic bag and leave until doubled in volume – this will take 2-3 hours.
Grease a large baking sheet. Transfer the dough to a lightly floured surface, divide in half and shape into two rounds. Place on the baking sheet, cover with a tea towel and leave to rise until doubled in volume (approximately 1 hour).
Score the tops of the dough rounds and sprinkle with the remaining oats. Bake for 40-45 minutes, or until the bottoms of the loaves sound hollow when tapped.