which fire alarm certificate for additional detectors in village hall extension

[Robertbaker63]

got to add in some breakglasses, ceiling detector and sounder to an existing fire 12v fire alarm system in a local village hall as theve put a new room on the side
which cerrtificate would i have to fill out? im a full napit member

 

[westward10]

See Modification Certificate in BS5839-1.