This first part of TGS takes place in Bethnal Green, an infamous Victorian slum which, in this alternate universe, is plagued not only by crime and poverty but also a frequent influx of supernatural creatures. I chose it mostly because it was a part of London's East End (generally, the place where Unpleasant Things Happened) but it wasn't Whitechapel.
Whitechapel is a popular neighborhood to use in Victorian-y Steampunk-y stories--especially Jekyll and Hyde stories-- because that is the neighborhood where the whole Jack the Ripper thing went down. Jack the Ripper is fine, and all, but he usually doesn't do much besides provide a light Shamylan twist in an otherwise fictional story: Picture a tv show with two police officers on the hunt for the man who murdered the nameless woman from the cold open. They discover a blood-stained note and begin to read. Close-up on the note, slow pan down to reveal: Jack the Ripper (dun dun duuuuun!!!!!!! New B-Plot unlocked!!!!!!)
Anyway, I've never been that into the Ripper murders, so Bethnal Green it is.