In a large bowl cream together the butter, brown sugar and white sugar until smooth. Stir in the egg and vanilla. Sift together the flour, bicarbonate of soda, salt and baking powder; stir into the creamed mixture. Add the oatmeal, crushed cereal and coconut then mix until combined.
Drop dough by teaspoonfuls onto a baking tray. Biscuits should be about 5cm apart. Bake for 10 to 12 minutes in the preheated oven. They should be light brown at the edges and on the bottom. Remove from baking trays to cool on wire racks.