Seems you haven't unlinked your device properly, in advance, before link it again. Dropbox service counts the connections/links made, not devices! That's why device could appear more than once at the list (as a connection) and the connection not refused properly will stay till remove it by hand. Such a state could come up as a result of uninstall the application before unlink it in advance or system maintenance resulting in unintentional link break, for example. You can remove/retire old connection using trash icon next to the link on the same line in the list.
... one with location as 'Rotherham'. I've never been to Rotherham! ...
Dropbox (and not only) decides where are you according your IP provided from your ISP. Very often this IP is used in many different places (it could be shared in fact). That's why you can "appear" in place you have never been (or at least not with your machine). My "place" changes from time to time, even I have never changed my access point. That's it. Nothing strange. It means that your ISP has service coverage there (Rotherham) together with the place you are residing on.