Sister Jayanti has not witnessed the happenings. She speaks only of whatever she has herself heard from Dadi Janki, most probably, who is only an ordinary human being and as anyone has her own subjective perceptions. For example, once asked a man from the station at Abu Road who knew Lekhraj Kirpalani has said that, "yes, i knew this man. He was definitely a very good man, but was definitely not God". There are a variety of perceptions; one can call him God, other not.
Golden Circle could have existed at that time, like people talking amongst themselves and creating this name, but it is one thing what people think and something else that God reveals through his knowledge. Like now, no matter in the latest Avyakt Vanis Avyakt BapDada may say that numbers are not fixed, you may love the Dadis, but the numbers are not fixed, some may think that BapDada is just speaking like that and Dadi is definitely a fixed number.
The only pure and reliable source of information is the Murli. There is difference between historical, scientific and other type of knowledge we may get from human beings - be it in a form of sentiments from the past, or something they could have learned themselves. There is only one source of spiritual knowledge that gives it without study. This knowledge is new and new points emerge all the time. It cannot be found in any book, the recollections or recordings of any human being, even in the Murli. It concerns the matters of the soul, the Supreme Soul and the world drama.