In a glass mixing bowl, mix water and oil thoroughly. Sift flours on to the liquid, stirring with a blunt knife. You should end up with a soft pastry dough. Cover and refrigerate briefly. After making the filling of your choice, grease a 21cm round pie dish with sunflower oil. Break the pastry into two parts, size ratio about 3:2. Roll out the larger one and place it carefully into the pie dish, so that the base and sides are covered. Scoop filling into pastry case, then roll out the other half of the pastry and use as a lid, pinching the edges of the two cases together all around. Prick the top case in several places with a fork. Bake pie for about 40-50 minutes at 200'C.