Combine the oats, puffed rice, coconut and cranberries in a large mixing bowl. Mix well then add the sunflower seeds.
Melt together the sugar, butter and golden syrup in a saucepan over a medium heat, stirring occasionally. Stir into the dry ingredients, working quickly to combine as thoroughly as possible. Pour into a 20cm square tin and level with the back of a spoon. Leave to set until cool.
Turn out onto a chopping board once cool and cut into rectangles. Serve stacked on a presentation board separated by a napkin.