what are three things in stave one that proves the setting of the story is in england in 1843

I don't know about 1843 in particular but certainly we are looking at the eve of the industrial revolution or thereabouts. A Christmas Carol is very much like Dickens's novel hard time except a little more festive! Dickens's 1843 London still had horse and buggies, lighting was candle light or some combustable fuel. Coal was the primary heating fuel (as we see in Ebenezer's office). Victorian values and attire resonate through the story as well.