Combine the water, eggs, egg yolks, olive oil and honey in a large mixing bowl. Whisk until well combined, then add 500g of the bread flour, the yeast and salt. Mix together until smooth and combined. Leave to prove for 15 minutes. Add the remaining flour in 4 even batches of 125g and combine until you have a dough. Turn out onto a lightly floured surface until you have a soft, elastic dough, using a little extra flour if the dough is too sticky. Once smooth and elastic, lightly oil a large bowl and place, the dough in it. Cover the bowl with a damp cloth and allow the dough to rise until doubled in size; roughly 60 minutes. Remove the dough from the bowl after proving and cut into three. Roll out into even shaped sausages. Connect the three pieces of sausage-shaped dough at one end. Braid the dough by bringing the right side across the middle piece of dough so that it now sits in the middle. Next, bring the left piece of dough across the middle piece so that it sits in the middle. Continue in this fashion until you have to pinch the ends of the dough together and tuck them neatly under. Carefully lift onto a lined baking tray. Preheat the oven to 200°C. Whisk the egg whites until frothy then brush the bread all over with it. Cover the braided dough again and allow it to prove for another hour or until doubled in size. Remove the cover then brush again with the egg white, sprinkle the sesame seeds on top and bake for 20 minutes. Turn the bread around, reduce the oven to 180°C, and bake for a further 20 minutes until golden brown in colour all over. Remove and allow to cool a little before serving.