Actually, an unpublished English translation exists. In her foreword to the Finnish book the editor, Ms Viherjuuri tells that her father, who obtained the publishing rights in 1939, originally planned to publish the book in Finnish, Swedish and English. The project was put on hold because of the advent of WWII. But apparently the translations were there. The Viherjuuri family remained in contact with Virubova for the rest of her life but no book came out during that time.
In 1984 Ms. Viherjuuri recieved a copy of the Virubova manuscript in English from a family friend from Germany. During the war her father had given the copy to this friend for safekeeping outside Finland (presumably for fear of a Soviet occupation or other hazards of the time). The friend had kept the papers for more than 40 years. Now this event inspired Ms Viherjuuri to finally publish the book in 1987 in Finnish and Swedish.