Registering a building for worship and for marriage
There are rules about where marriage can legally be solemnized and places of worship must be registered for the purpose. Many are already registered. However if you are a minister, proprietor or trustee of a building you would like to have registered for worship and the solemnization of marriage information and application forms are available at www.gro.gov.uk/content/marriages/index.asp 

To make application the forms on completion should be returned to your local register office with the relevant fee, a sketch floor pan and a timetable of the weekly use of the building. The Registrar General will consider the application. When authorized the Register Office will place a Notice in the local press and the London Gazette informing the public that the building is registered for worship and marriage.

Further information and advice see link above or contact your local Superintendent Registrar at the Register Office