I teach part time on the LLM course at UCL. The UCL Faculty of Laws lives in Bentham House, an interesting 1930s art deco building that used to be the headquarters of a major trade union. The building is close to Euston Station and is a few minutes walk from the main quad of UCL, and from some of the interesting streets of Bloomsbury, with bookshops and cafes.
I am a big fan of UCL. But I also rate KCL. I prefer both to the LSE, because I think that UCL and KCL provide better experiences for students. Friends who were undergraduates at UCL tell me that they loved it there, although they studied there many years ago.