Preheat oven to 180°C/350/f/Gas Mark 4. Line a large baking tray with baking paper.
Mix the flour, oats, baking powder, salt, cinnamon in a large bowl.
Cream the butter & sugar, then add eggs and milk, beat well.
Combine the two mixtures. Add the chocolate bits and mix well.
Drop spoonfuls of the batter onto the tray, leaving about 5 cm space between them, then squash them down a bit.
Bake for 10-15 minutes, until golden brown.
Allow the cookies to cool for a couple of minutes then move them to a wire rack to cool completely.