I saw the "Carol of the Bagpipes" for the first time last Christmas while looking through a book of carols with my singing instructor. It's really pretty, but also having just worked on "He Shall Feed His Flock" for an audition, I fail to note any resemblance, other than that Handel was obviously using the Siciliana as a model. The tunes did not seem to match. Have you any other basis for this?