I am Ran Prouse and have been working on the Prowse/Prouse families in England and the U.S. for nearly 50 years now. I would like to work with you to answer some of the questions that are being raised. I would like to on your Trusted List.
In regard to Chagford and Waye Barton and the family connection I have some info. I am quoting from Susan's book"
"The medieval years in this remote part of Devon were indeed dominated by by the family ofPROUZ of Gidleigh, as well as by the other great medieval families of Bonville, Webbery and Gorges, to which the Prouz's were related. By the 14th century, the Gidleigh Branch of the family had, as we have seen, gone into the female line, the manor and castle of Gidleigh passing to the de Moelys family through Alice le Prouz's marriage to Roger de Moelys. The CHAGFORD branch of the family, however, flourished and remained the oldest and most stable of Chagford's nobility until the 17th century. The churchwarden's accounts are full of the names of the many members of the family who held offices as church wardens, contributed to many community projects and were baptized, wed and finally buried in Chagford Church. (History of Chagford)
About 1300, Sir William le Prouz, the last of our name to hold Gidleigh Castle, bequeathed several of his "wheat fields, lands, and holdings" in Chagford to his youngest brother, William Prouz (see Deed of Gift on page 49) William Prouz, born circa 1250, married Elena, daughter of Geoffrey de Ponte of Cjhagford. The de Ponte's owned the Cloth Mills at Chagford Bridge - the bridge, which led up to Gidleigh and Throwleigh, was in existence as early as 1224, so not was still fairly new at the time that William Prouz and Elena set up homie in Chagford, which must have been around the early 1270's or 80s.
It was William and Elena Prouz's son and heir, yet another William Prous (remember the ancient Prouz slogan - "whereof most were called William") who came into possession of the Manor of Waye Barton. Ion 1345, just eight years after the outbreak of the 100 years War with France and a year before the victory at Crecy, Robert de Waye "released all his right of land in Chagford to William Prouz, a younger son of the Gidleigh knights.
The Prouz family owned Waye Barton from 1345 until the late 17th century, when it passed to the Courtenays through the marriage of Philippa Prouz, only surviving sister of John Prouz, last of the male line of this branch of the family (and whose marble monument can still be seen in the south chancel of Chagford Church) to Richard Courtenay. With John Prouz's death in 1664, this "ancient line disappeared fro the parish."
Waye Barton was home to 10 generations of the Prouz family.
As this states Chagford and Waye Barton belonged to the same family through a younger son.
In regard to Peter and Julien, I don't think they siblings.
It is my belief that the de Cailly family is the connection to the Prouz family. No matter the spelling they were connected.