Line a 12-hole muffin tray or deep bun tin with paper muffin tray or deep bun tin with muffin cases. Mix the flours, baking powder, oatmeal and sugar in a bowl. stir in the chopped apples and sultans or raisins.
In another bowl, beat together the butter, yogurt, milk , egg and honey. Add this mixture to the dry ingredients and stir quickly and briefly, until just incorporated; do not over-mix.
Divided the mixture between the paper cases and sprinkle with a little extra oatmeal. Bake in a preheated oven at 200c (400F) gas mark 6 for 18-20 minutes until just firm to the touch. Transfer to a wire rack to cool.
Pop the cold muffins into a lunch box, or serve warm with stewed apple or plums; or low-sugar plum jam.