Pre-heat oven to 175°C bake. Line the base of a 19cm x 30cm slice tin with baking paper.
Combine the flour, baking powder and Chelsea Soft Brown Sugar in a bowl, add the melted butter and stir well until combined then press mixture evenly into the prepared tin to form a base. Bake for 10-12 minutes until pale golden and just set.
Melt together the condensed milk, Chelsea Golden Syrup and butter in a saucepan over low-medium heat, stirring until golden and thickened (watch the bottom doesn't burn). Set aside to cool for 5 minutes while making the topping.
Combine coconut, oats, Chelsea Soft Brown Sugar and butter and stir well.
Pour the caramel over the par-baked slice and carefully spread over topping mixture, pressing into the caramel lightly. Bake the slice for a further 10-15 minutes until golden and bubbling.
Set aside to cool before cutting into slices.