Introduce overseas constituencies

Currently British citizens who live abroad still vote in Parliamentary elections in the constituency in which they were last registered, even though they often have no remaining ties to that location. Instead, introduce one or more overseas constituencies whose MP(s) specifically represent the people who now live there, similarly to the [French system](https://en.wikipedia.org/wiki/Constituencies_for_French_residents_overseas). This is even more important in the UK where there is a much closer tie between an MP and their constituents.