Preheat the oven to 200 degrees Celsius or gas mark 6.
In a large bowl, mash the bananas and stir in the oats.
Add the maple syrup, water and dark chocolate chips (save a few for sprinkling on the top).
Mix well and place into a lined 20cm baking tray. They will only fill two-thirds of the tray to make 6 bars.
Bake for 25 - 30 minutes.