Preheat oven to 150°C Line a baking tray with non-stick baking paper.
Sift together the flour and cinnamon in a medium bowl. Add the rolled oats, coconut, caster sugar and brown sugar, and mix well.
Combine the butter, golden syrup and water in a small saucepan, and stir over medium heat until the butter melts and the mixture is well combined (or this step can be done in the microwave). Remove from heat and stir in the bicarbonate of soda. Add immediately to the dry ingredients and use a wooden spoon to stir until well combined.
Roll walnut-sized portions of mixture into balls and place on the lined tray about 5cm apart. Use your fingers to flatten each slightly (until they are about 1cm thick) and bake in preheated oven for 18 minutes for crisp on the outside and chewy in the centre (see note).
Remove from oven and set aside for 5 minutes to cool slightly before transferring to a wire rack to cool completely. Repeat with the remaining mixture.
NB/#These biscuits will keep in an airtight container for up to 1 week.
You can cook the biscuits for 16 minutes for a chewy biscuit or 20 minutes for a crisp biscuit.