Preheat oven to 220℃ (200℃ fan forced). Line a large baking tray with baking paper and set aside.
Combine self-raising flour, bran and salt in a bowl. Add the butter, then using your fingers, rub the butter into the flour mixture until it resembles fine breadcrumbs (there will still be chunks though due to the bran). Make a well in the centre and pour in the milk. Mix to a soft dough.
Transfer dough to a lightly floured surface and knead gently until it just comes together. Pat the dough in a rough rectangle shape then using a rolling pin, roll out the dough into a rectangle about 30cm x 40cm and 5mm in thickness.
Combine all filling ingredients in a bowl and season with a pinch of salt and pepper. Spread the filling evenly over the dough leaving a 2cm boarder all round.
From the long side, roll the dough up firmly and press the ends close to seal. Transfer to prepared tray, shaping the dough into a horse shoe style shape. Using a sharp knife, makes slits in the top of the dough all round at 2cm intervals. Brush with top with lightly beaten egg or milk.
Bake in the oven for 25 minutes or until golden brown. Cut into slices to serve. May be served hot, warm or at room temperature.