I got the information during the oral arguments of the Padron case. Also a federal court case in Louisiana where they did indicate that CCJW is a US Corporation that handles the legal affairs of the US Service Department.
It is also when at conventions or assemblies when they make the announcement that because funds for these events are handled by the local branch office please make checks payable to Christian Congregation of Jehovah's Witnesses.
In Britain, there is no corporation that is called Christian Congregation of Jehovah's Witnesses. There are two main corporations. Watchtower of Britain and the International Bible Students Association.
IBSA mission is stated as: Promoting the Christian religion by helping congregations of Jehovah's Witnesses & others with their spiritual & material welfare. We provide facilities for printing Bible literature & housing for members of our order of special full-time servants. We distribute religious literature freely to all who will read it. Conventions for Christian education are arranged & the public are invited.
Watchtower of Britian mission is stated as: 1. PRINTING AND DISTRIBUTING BIBLES AND BIBLE-BASED LITERATURE IN SEVERAL LANGUAGES. 2. FUNDING THE CONSTRUCTION OF PLACES OF WORSHIP IN VARIOUS COUNTRIES. 3. SUPPORTING CONGREGATIONS AND ASSOCIATIONS OF JEHOVAH'S WITNESSES AND OTHERS IN CONNECTION WITH THEIR SPIRITUAL AND MATERIAL WELFARE IN THE UNITED KINGDOM AND ABROAD, BY MAKING DONATIONS AND ADVANCING THE CHRISTIAN MISSIONARY WORK.
So my mistake it seems like the service department in Britain would actually probably fall under the corporation of the Watchtower Bible and Tract Society of Britain.