Preheat the oven to 350 degrees F (175 degrees C). Grease a baking sheet or line with parchment paper.
Mix together oats, sugar, flour, and coconut in a large bowl. Set aside.
Melt together butter and golden syrup in a small saucepan over low heat. Combine boiling water and baking soda in a small bowl, then add to melted butter mixture. Pour over oat mixture; mix until well combined. Drop spoonfuls of dough 2 inches apart onto the prepared baking sheet.
Bake in the preheated oven until edges are golden, 18 to 20 minutes. Cool on the baking sheet briefly before removing to a wire rack to cool completely.