Preheat an oven to 190 C / Gas 5. Grease 12 muffin cups, or line with paper cases.
Combine the oat bran and wheat bran in a large bowl. Stir in soured cream and milk. Allow mixture to stand for 10 minutes. Combine flour, baking powder, bicarb and salt in a separate bowl. Gently stir blueberries into the flour mixture, carefully coating all the blueberries with flour. Stir vegetable oil, orange juice and zest, egg and vanilla extract into the bran mixture. Combine flour mixture with the wet ingredients until just blended. Drop batter into muffin cases.
Bake in the preheated oven until a skewer inserted into the centre comes out clean, 15 to 20 minutes. Cool in the tin for 10 minutes before removing to cool completely on a wire rack.