George P of the Shenandoah thus may have also had the given name Paul, thus his use of the middle initial. Though we have no known connection between George P and Paul Canning of Garvagh, the latter was one of the sons of Stratford Canning ("Counsellor Stratford"), grandfather to George Canning the PM and Stratford de Redcliffe Canning the great statesman and diplomat at Constantinople, Washington DC, Switzerland, and Greece. Unlike two of his brothers George and Stratford (the fathers of the two famous statesmen, respectively), Paul was not banished from Northern Ireland, but stayed on and enjoyed his inheritance there; he was the father of George Canning the first Baron Garvagh, a title which survives to this day.
There is a book which I must read, _Heir and No Heir_, about the disinheritance of George and Stratford Canning by their father in Garvagh, and the inheritance of Paul. This book was written by Alfred Stratford George Canning, another descendant of Counsellor Stratford.
For a good outline of the prominent Cannings, see Charles Hillman's work at
http://www.kittybrewster.com/ancestry/canning.htm