Combine the flour, salt and yeast in a large mixing bowl. Rub the butter into the flour mixture using your fingertips until you have a mixture resembling fine breadcrumbs. Combine the warm milk and water in a jug and pour into the flour mixture, mixing well with a wooden spoon until you have a soft dough. Turn out onto a lightly floured work surface and knead for 15-20 minutes until you have a smooth, elastic dough. Place the dough in a large mixing bowl and cover with a damp tea towel. Leave the dough to rise in a warm place until doubled in size; roughly 1 hour. After proving and doubling in size, remove the dough from the bowl and knock it down using your hands. Knead the raisins into the dough at this point. Divide into 8 even portions and shape into rectangles. Arrange, spaced apart on an oiled baking tray and cover with a piece of oiled clingfilm, leaving it to prove in a warm place for a further hour until doubled in size again. Pre-heat the oven to 200°C. Bake for 10-12 minutes until risen and cooked through. Meanwhile, whisk together the sugar and milk to make a glaze. Combine the oats and sesame seeds in a bowl. Remove the rolls when ready and brush all over with the milk glaze. Sprinkle the oat and seed mixture all over the rolls so that they stick to the them. Allow them to cool completely on a wire rack. Serve on a wooden platter.