I was in (email) conversation with Lesley Champion, my Australian correspondent, about the Bristol origins of her Fitz-Henry line in the late 1700s. There are several Fitz-Henry/Fitzhenry families mentioned, and they seem to be Irish Catholics (probably the worst combination you can have at this time from the genealogy viewpoint!).
A name that has cropped up in several references is Patrick Fitz-Henry. I first found him in the London Gazette, where he is prominent in the Bankruptcy columns. In fact he seems to have the distinction of becoming bankrupt twice in the 1790s. He is listed variously as a "Merchant and adventurer" and a "ship owner" trading out of Bristol and Newfoundland. A Google reference then more sinisterly leads to a pay-per-view article in the History in Africa journal which names him as a slave trader with his ship the Maria. He is also listed on the Merchant Network website as being a slave trader out of Bristol.
The last reference is via Google books and in George Oliver's "Collections Illustrating the Catholic Religion..."(1857), the description of the attempt to establish a Catholic Mission in Bristol told that
"the congregation could contribute but little and even that little, collected by committee, was unadvisedly placed by its members in the hands of one Fitz-Henry, an Irish merchant, and was irrevocably lost by his bankruptcy."
Any further information about Patrick Fitz-Henry most welcome.