Brendan, I came across your posting while researching my little known French background. Jean Marie and Annie Elizabeth (Archbold)Guillevie are my Great-Grandparents.
One of their sons, my grandfather, Sidney Joseph Guillevie was born in Sidney about 1893 and ended up living with his maternal grandmother Catherine Archbold in Goresbridge-county Kilkenny, for reasons unknown to me. He then emigrated to the US (Philadelphia), and anglicized his last name to Gilbey. Unfortunately, I'm looking for more details myself, and wish I had more to offer. John Gilbey