What’s the difference between the BA and BSc?
It tends to be pretty irrelevant whether the degree is a BA, BSc or BSocSci: whilst there are (often substantial) differences between the way politics is taught at different universities, the nature of the course is rarely predictably related to the type of degree awarded. Oxford, for example, is generally regarded to have high levels of theoretical study and history all the way through their degree programmes, to Essex which is known for a highly quantitative course. As a social science, politics hovers between the arts and sciences and no-one can quite agree where to put it, and universities tend to decide completely arbitrarily whether theirs is a BA or BSc! This also relates to the degree title: just try not to read too much into it, and check the modules offered.