Combine flour, oats, baking powder, and salt. Cut in butter until mixture resembles coarse crumbs. Stir in blueberries, toss to coat.
In a medium bowl stir together, bananas, brown sugar, sourdough and egg.
Stir banana mixture into dry ingredients until moistened. Turn dough onto well floured surface.
Knead 5 to 10 times (dough will be very sticky) Pat into a 12 inch circle. Cut into 10 to 12 scones. Transfer scones to a baking sheet lined with parchment paper. Place a few sliced almonds on top of each scone, press down lightly,
Bake at 375 degrees for 12 to 15 minutes or until golden brown. Remove scones from oven, transfer to wire racks, cool slightly.
Make Lemon Glaze: Whisk together confectioners' sugar, lemon juice, lemon zest and vanilla extract. Whisk in enough milk to reach desired drizzle consistency.