I'm not in the faculty of laws, but it seems OK so far in in the faculty of arts and humanities. I'm a commuter student so honestly I don't spend a great amount of time on campus. The SU offers a huge variety of stuff and London itself also has a huge range of options of stuff to do, so for things outside your course it's really what you make of it.
In terms of community I think this depends a bit who you engage with. Not sure what you mean about community and types of people to meet, it's more or less the same range as at most large research focused universities. Good chunk of international students, fair variety otherwise. Also a good chunk of Londoners living at home while studying there it seems.
To be honest I think a lot of the things you are asking are really dependent on what you as an individual make of them - social life and co-curricular activities are really things that you get as much out of as you put into them. How you prioritise that will be up to you.