I forwarded your email to my mother asking her to find out, this is her reply:-
I dont think so as they are not names my Mum or me recognise. My Grampy had a brother John who everyone called Jack but I don't think that has anything to do with it. The dates would make the John this chap is talking about 41 when my grandfather was born and although he was one of eight I don't think they would have been having children in their 40s. Anyway my great grandmothers name was Mary, according to my Mum. But I think my grandfather had an Aunt Jane but I am not sure how that would work in.
So I am not sure whether any of this information is of help to you.