To make the dough, mix the yeast with the warm water, sugar and oil and leave for 1-2 minutes. Add the flours into a mixing bowl with 1/2 tsp salt and briefly mix before making a well ready for the liquids. Pour in the yeast mixture and stir into the flour using a fork, until the mixture comes together and can be finished off by hand. Knead the dough for 3-4 minutes on a floured surface, then place in a clean, lightly oiled mixing bowl. Cover the bowl with a damp tea towel and leave in a warm place for 1 hour or until it has risen to double its size.