Using "sorry" to mean "pardon"
Solution 1:
The NOAD reports the following entry for sorry:
used as a polite request that someone should repeat something that one has failed to hear or understand: "Sorry? In case I what?"
It is not marked as being chiefly British. In ten years I have visited the USA, I have heard sorry being used when somebody didn't hear or understand what somebody else said.
Solution 2:
I've lived in both the UK and the US and my anecdotal experience is that "sorry" is very much more common in the UK than the US. It sounds very British to my ear. In the US "excuse me?" or "huh?" are considerably more commonly used to serve this purpose.
However, as the saying goes, data is not the plural of anecdote.