American Unitarians and Universalists have, for about a century, kept and extended fellowship through a series of institutions, the largest and most notable today is the Church of the Larger Fellowship.
The British (and independently the Scottish) Unitarians and Free Christians have a similar fellowship. And the Quakers have one globally.
But when I discovered the Coptic-jurisdiction British Orthodox Church had one, I knew I had to investigate. And thus the background for the next couple of posts.