With a rolling pin or flat mallet, pound candy to break into large chunks. Lay cut sides of bananas in crushed toffee and press gently to coat heavily. Reserve remaining toffee. Scrape into a small bowl. Working quickly, scoop ice cream into balls and place equal portions between banana halves.
Sprinkle scoops equally with malted milk ball chunks and the remaining crushed toffee.
Ladle the warm chocolate sauce over the top.