The United Reformed Church 
The United Reformed Church was formed by the union of the English Presbyterian
Church, Congregational Church (1972) and the Churches of Christ (1981). There
are some 1300 local Churches. There is a description of its doctrines and practice
on the URC's national pages. The same pages also provide
general description of the ancestry
of today's Reformed Christians. More specifically UK-based is a short history
of one of the URC's original constituents, English
presbyterianism.
The URC's national pages have lists of local
Churches and URC
organizations.
If you are totally bewildered by the differences between the denominations
in England, try Rowland Croucher's review (really a collection of excerpts)
of Gavin White's Book "How the Churches Got
to Be the Way They Are".
