In a large bowl, cream together the white sugar, brown sugar and butter until smooth. Beat in the eggs one at a time then stir in the vanilla. Combine the flour, baking powder and bicarb soda; stir into the creamed mixture until just blended. Mix in the rolled oats and sunflower seeds. Stir in coconut if desired. Drop dough by heaping teaspoonfuls onto ungreased baking trays. Leave room for spreading.
Bake for 10 to 12 minutes in the preheated oven or until the biscuits begin to brown around the edge. Allow biscuits to set for a few minutes on the sheet before removing to wire racks to cool completely.