Blend the oats in a food processor until they are finely ground, or chop them very finely with a knife. Add the flours, sugar, bicarb of soda and butter.
Pulse the butter and add a bit of milk into the dry ingredients until it starts to clump together.
Roll out the digestive mixture between 2 pieces of clingfilm until it is around 1 centimeter thick.
Use a 5 centimeters round cutter to cut biscuits out of the dough and bake for 8-10 minutes, or until golden brown.
Caramel
To make the caramel, combine the sugar and syrup in a saucepan and melt over a medium heat until it reaches 155 degrees.
Remove from the heat and stir in the butter, then heat to 127 degrees. Stir in the double cream and salt before pouring into a greased and lined baking tray to set.
Press digestive biscuits into the caramel layer, then dip caramel side down into the dark chocolate.