Mix buttermilk and oats in a small bowl. Let stand for 15 minutes.
Sift flours, baking powder, bicarbonate and cinnamon into a large bowl. Stir in wheatgerm and husks from wholemeal flour.
Whisk eggs, sugar, oil and vanilla in a medium bowl. Add buttermilk mixture. Add this mixture to flour mixture and mix with a rubber spatula just until flour mixture is moistened.
To cook pancakes: coat a large non-stick frying pan with cooking spray. Heat over medium heat. Spoon about ¼ cup batter for each pancake into the pan and cook until bottoms are golden and small bubbles start to form on top, about 2 to 3 minutes. Flip pancakes and cook until browned and cooked through, 1 to 2 minutes. (Adjust heat as necessary for even browning.) Keep pancakes warm in a 90°C oven while you finish cooking remaining batter.
Top with bananas and drizzle with maple syrup. Wrap any leftover pancakes individually in plastic wrap and refrigerate for up to 2 days or freeze for up to 1 month. Reheat in a toaster or toaster oven.