Sorry if I have come across as being in doubt about your connection to Peter A Campbell. That is absolutely wrong. I am looking for proof of my assumption that Peter A is a half brother to my grandfather through his father John. If I can find descendants of Peter then it is possible that a DNA may be in order. Since a DNA is fairly expensive, I must tread slowly. Should a DNA be positive, then we would be closely related.
I will be going on a search for the book by RB Campbell as it may have some important info for my search. Any and all further info that you may have is very gratefully accepted.