Place the sugar, butter, honey and golden syrup in a saucepan over a medium heat and heat, stirring occasionally, until the butter has melted and the sugar dissolved. Remove from the heat.
Stir in the mashed banana and oats and mix well. Spoon one-half of the oat mixture into the prepared tin, sprinkle over the banana chips and top with the remaining oat mixture. Press down and level the top.
Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 20–22 minutes until golden.
Remove from the oven and cut into 12 bars while still hot. Leave to cool in the tin.