Mix buttermilk and egg. Add high fibre bran, stir and let stand for 5 - 10 minutes or until the cereal has softened.
In a separate large mixing bowl, sift flour, baking powder and salt.
Add the cold margarine, cut it up and then tub it with the dry ingredients between your fingers until the mixture resembles fine breadcrumbs. Lift you fingers above the bowl while rubbing to aerate the mixture.
Make a hollow in the centre of the flour mixture and add the buttermilk mixture, cutting in the liquid with a knife. Cut in the milk or water, add just enough to make a medium to firm dough. Take cake not to over mix as the dough will become too elastic and the scones will be too heavy.
Turn the dough onto a lightly floured surface, and pat out the dough by hand to remove any cracks and to form and even 2 cm thick circle. Flour a large fluted cutter and cut the dough into rounds. Repeat with the leftover dough, working it as little as possible, to get 9 large scones.
Place on a lightly greased baking sheet and bake for 10 - 15 minutes at 200°C (the scones should be golden brown and well risen).
Remove, cool, split oven and spread with butter and jam or cheese.