In another thread outoftheorg said he was unaware that all congregations in the U.K (except Scotland) were registered with the Charity Commission for England and Wales.
The following link will take you to the first web page of the names of all these congregations.
It shows the name of the Presiding Overseer (correspondent), his address and often his telephone number.
Cut and paste this into your browser to check the info.
link
(Sorry, unable to properly format the page)