Activate the yeast. Combine warm water, a pinch of the fermenting agent, and a teaspoon of the golden syrup in a large bowl. Let this mixture sit for 5-10 minutes until it becomes foamy. This shows the fermenting agent is active.
Combine wet ingredients. Add the remaining golden syrup, salt, and oil to the foamy mixture. Stir everything well until fully combined.
Incorporate the dry ingredients. Gradually add the whole grain flour and two cups of all-purpose flour to the wet mixture. Mix until a shaggy mass forms.
Knead the mixture. Turn the mixture out onto a lightly floured surface. Knead for 8-10 minutes until it forms a smooth, elastic ball. Add more all-purpose flour a tablespoon at a time if the mixture is too sticky.
First rise. Place the kneaded mixture in a greased bowl, turning once to coat. Cover it with plastic wrap or a clean kitchen towel. Let it rise in a warm place for 1-1.5 hours, or until it has doubled in size.
Shape the loaf. Gently punch down the risen mixture to release air. Shape it into a loaf and place it in a greased 9×5 inch loaf pan.
Second rise. Cover the loaf pan and let the dough rise again for 30-45 minutes. The mixture should nearly double in size and crown over the pan.
Bake the bread. Preheat your oven to 375°F (190°C). Bake for 30-35 minutes, or until the crust is golden brown. The internal temperature should be 200-210°F (93-99°C).
Cool completely. Remove the baked bread from the pan immediately. Place it on a wire rack to cool completely before slicing. This prevents a gummy texture.