That's interesting. I've only managed to locate and visit Grace Communion International congregations. I can't find any active WWCG splinter groups locally. I was told by a Grace Communion International member that there were a few adherents of a splinter group called "United Church of God" in Scotland but they didn't last long and have no active congregations in Scotland. Maybe one in Newcastle, I was told.
This is something I have found: just because a group has a presence on the Internet, doesn't necessarily mean they have a functioning church in the real world. I think some of the WWCG splinter groups faded away pretty quickly and exist in name only. (On that, I suspect that the "Lord's Witnesses" may be as real as Gordon Ritchie's chronology. Has anyone ever been to any of their meetings to verify they exist?)
The church headed by Jospeh Tkach (pronounced t-catch) is by far the biggest, although it has shrunk a lot. By the way I heard from an insider that Tkach is retiring next year. I wonder how that will work and if it will survive without him.