Tinie Tempah follows British homeowners as they realise their dreams by embarking on ambitious home extensions. Here he joins a couple of art deco obsessives as they try to transform their typical west London terraced home into a Great Gatsby-inspired 1920s palace. And on the Norfolk Broads, he meets a family risking the picture-perfect look of their thatched cottage by adding an experimental eco-extension inspired by their love of sailing