Place carrots, potatoes and onions in bottom of slow cooker.
Trim roast and cut into cubes. Toss cubed beef with flour, garlic powder, paprika and herbs. Heat oil in pan until very hot and toss beef in to quickly sear cubes on one side. Add beef to slow cooker on top of vegetables.
Add stock, water, 1/2 bottle ale and stock cube. In a bowl, mix together cornflour and 1/4 cup ale until cornflour is dissolved and add to slow cooker. Close lid and set slow cooker on medium-low for 8 hours.
When it is finished cooking and you are ready to eat, roll out a sheet of puff pastry and cut into four quarters. Preheat oven according to the package directions on the puff pastry.
Divide the meat and vegetable mixture from the slow cooker into four individual pie tins. Lay a square of puff pastry on top of each tin, place all on a baking sheet or two and put in oven. Bake until the pastry is golden brown on top.