Combine both flours, blended oats, yeast, and salt in a large bowl.
Mix the honey, sunflower oil, and warm water in a separate jug.
Create a well in the dry ingredients and pour in the liquid mixture.
Add the beer and stir until the dough is a thick, sauce-like consistency.
Cover the bowl with a damp cloth and rest in a warm place for an hour.
Melt butter in a large non-stick frying pan over medium heat.
Pour a ladle of batter into the pan and swirl to cover the surface.
Cook for five minutes until the underside is brown and crisp.
Flip the oatcake and cook the other side in the same manner.
Transfer to a cooling rack and repeat with the remaining batter.