Where to live in London for SA

Assuming you prioritise getting the FT offer over having a fun summer, stay as close to the bank as possible. Walking distance is ideal - it's the only fresh air you'll be getting all summer. Great to avoid the sweaty summer tube too. Budget is personal preference, personally I think spending up to £400/week is acceptable even though it may seem excessive. You want to live in a nice place, you'll need to feel comfortable and relax when (if) you get some chilled time at home. Congrats on the offer!

Where is the bank located?

I lived in St. James's, which was nice, as when I got out late I could walk to Leicester Square where some quick food places were still open for a second dinner. The only downside was I had to transfer Tube lines in the morning, but still a 15 min commute tops.

I had to wait for a visa, so most student housing was taken by the time it came through, but I know a lot of interns at my bank lived in various student accommodations.