In the event of a tie, it is 'Games Won' which is the first determinant of standing; and then only after that does N.R.R. come into play.
So since England and South Africa have both won 3 games, N.R.R. does come into play and England are third... right?
Well... yes... but... technically, both 'Games Won' and N.R.R. are only applied once all games have been completed; therefore as things stand right now, England and South Africa are indeed "joint second"!