A lot depends on how you want to fund it. If you don't plan to teach, then it doesn't matter too much if your uni is a bit of a trek (I know Sheffield has a great Latin American Specialist - Jean Grugel). LSE is very good for developement studies, but Sussex, as far as I know, is more EU, so if you want to push the EU relations, that might be a good starting point. The LSE has a couple of LA specialists, but mainly in IPE/trade agreements etc