The most important things to think about being a student in London are -
a) London is a big place and students live all over the place - some in suburbs an hour away from campus. This can lead to a disjointed sense of community and often a sense of loneliness.
b) Its expensive. Not just 2nd & 3rd year private renting but transport, food and entertainment.
You can often get a better 'student experience' in a smaller city like Manchester, Leeds or Bristol where is cheaper and students live closer together.