Sift flour into a big bowl. Add the yeast and salt and stir in the seeds. Mix the yogurt, water and butter together and stir into the flour. Turn the dough out onto a floured board. Knead for 5 minutes. Put the dough back in the bowl, cover and let rise in a warm place until doubled in size. (2 to 4 hours depending on the warmth of the room) Punch down dough and knead for 1 minute. Cut it into 8 equal pieces and roll each into a ball. Sprinkle a little four on work surface and roll each ball out to an oval shape. Heat a griddle or heavy based frying pan until quite hot, brush it lightly with some oil, and cook each bread for about 3 minutes on each side. Keep the breads warm, wrapped in a clean tea towel.