Preheat oven to 150 degrees celsius (fan-forced).
Grease and line a 17cm x 28cm rectangular baking tray with baking paper and set aside.
Place the butter, golden syrup and water in a microwave-safe bowl. Microwave on 50% power, in 30 second bursts, stirring each time, until melted. Stir through the bi-carb soda. The mixture will froth up.
Add the rolled oats, flour, brown sugar and coconut and stir.
Fold through the chocolate chips.
Place the mixture into the tray and press down firmly.
Bake for approximately 25 minutes or until lightly golden brown.
Leave in the baking tray to cool for 10 minutes before transferring to a wire rack to cool completely.
When the slice has cooled completely, cut it into slices.