I graduated from LSE in Government and International History in 2014.
Teaching and resources were good, the opportunities to mix and debate views with people from all over the world were amazing. Try studying the history of the Middle East with a class mix of 2 Russians, some Americans, couple of Brits, an Israeli, a Kazahkstani and a couple of people from SE Asia. The varied views are amazing and I believe unparralled and impossible to recreate anywhere else in the world.
LSE churns out more Nobel prize winners and world leaders than any other university. The social scene is tough due to the massive mix of people and the lack of campus feel but my tip would be to join a society for something that interests you and you will meet people with shared interests (debate, sport, wine, travel etc). I also found mixing in the wider “London” scene to suit me more, I took dance classes outside of uni and got into the theatre scene.
I now work in an investment bank (though in an operations centre outside of London) and people are still impressed at where I got my degree. The careers service and advice and knowledge they offer to get you into your chosen line of work (banking, consultancy, not for profit, IR, politics, law) are unreal and available to you for 5 years post graduation
Take it, do it, be aware that it’s not your typical university experience but it will open doors for the rest of her life.