Paula Broadwell, the biographer with whom former CIA director David Petraeus had an extramarital affair, abandoned her bid for a doctorate from Harvard in 2007, failing to advance to PhD candidacy after four semesters at the Kennedy School of Government, and now faces the prospect of an ethical review at King’s College London, where she has resumed pursuit of a doctorate. The revelations about her mixed academic record add to the portrait of a principal figure in the Petraeus scandal who has refused to respond to multiple Globe requests for comment and hasn’t spoken publicly since disclosure of her relationship...