I was in my local tesco in Sheffield on Infirmary Road, browsing the Christmas Chocolate selection and stumbled across the large 390grams of Galaxy Chocolate, reduced to clear at half price. I don't know if this is nationwide. But it's definitely worth the price. Unfortunately, I didn't take a picture of the offer at the time.
Galaxy Chocolate 390 grams at £1.75 in-store at my local tesco, Sheffield infirmary road.