Preheat oven to 350°F. In a large bowl, combine the spelt flour, oat flour, coconut, baking powder, baking soda, salt, and lemon zest. Mix well. In another bowl, whisk together the yogurt, maple syrup, milk, and lemon juice. Add the wet mixture to the dry, and stir through until just combined. Scoop into a muffin tray with muffin liners (parchment liners work well), filling 12. Bake for 19-22 minutes, until set and golden. Remove and let cool in the muffin pan for a few minutes, then transfer to a cooling rack to cool completely.