Preheat the oven to 200ºC.
To make the cheddar scones: Place flour & butter into a bowl & use your fingertips to mix in butter until it resembles fine breadcrumbs. Add the cheddar & buttermilk, season with salt & pepper & mix until just combined. Transfer to a floured surface & bring together. Roll out to 2 cm round & score into squares. Transfer to a lightly floured baking tray. Brush with extra buttermilk & sprinkle with extra cheddar. Bake for 20-25 minutes or until golden & cooked through. Set aside.
To make the chowder: Heat butter in a large saucepan. Add garlic & cook for 1-2 minutes or until lightly browned. Add the flour & stir for 1 minute. Add potatoes & stock, bring to the boil stirring occasionally. Reduce heat & simmer for 10-12 minutes or until potatoes are cooked. Using a stick blender blend until smooth. Peel & devein the prawns, removing the tails. Return to saucepan & add the cream, corn & prawns & cook for a further 5 minutes or until the prawns are cooked. Season with salt & pepper. Top with creme fraiche, crispy chopped pancetta & baby chervil to serve. Serves 4.