There is a Saint Geoffrey of Clairvaux listed in Catholic Encyclopedia.
Is there a Saint Jeffrey in the Roman Catholic Saints?
Geoffroi, etc. = Geoffrey = Jeffrey
That said, it’s an interesting question. Let me go see what I can dig up among the English martyrs!
He was a student of the great Bernard of Clairvaux.
Apparently “Jeffrey” or “Jeffry” is often a Welsh spelling, and Genuki says there was an old parish Church of “St. Jeffry and St. Oswald” in Jeffreston, Wales. That’s an Anglican church, but it’s older than Anglicanism.
Here’s the Wikipedia entry on Jeffreyston, as it’s spelled today, with a picture of St. Jeffrey and St. Oswald’s.
The Dictionary of English Place Names says that the original name of the place (in Latin on legal papers) was “Villa Galfrid,” and Galfrid = Geoffrey, too. So it seems likely that the original Norman or Saxon landowner gave the church the name of his patron saint, St. Galfrid, and the name of the church and the town changed as English changed.
Here’s saints.sqpn.com about St. Galfrid/Walfrid. He was a married saint from Italy whose wife and kids also became holy. One of them wrote up his biography.
Under G in their alphabetical list, saints.sqpn.com has a ton of Ss. Geoffrey, though. If you look under J, most of them have also been called “Jeffrey.”
And then there’s St. Ceolfrid, St. Bede’s mentor, whose name has been mangled into lots of other names including “Jeffrey.” Life’s hard when your name is Old English. 