In a large mixing bowl, mix together plain flour, wholemeal flour, salt, sugar, and baking soda.
Pour in buttermilk and mix until combined.
Tip it out onto a floured work surface and knead slightly till combined.
Then form into a ball, and place on lightly greased baking pan.
Score bread using a knife.
Bake for 60-75 minutes or until skewer inserted comes out clean.
Notes
You can use all plain flour instead of mixing 50/50. We spread some cream cheese on the sliced up bread, topped it with smoked salmon, a little spritz of lemon, and garnished with fresh dill.