when we prepare our civil wedding we went to uk embassy to exchange his CNI i brought my birth certificate,singleness from NSO and postal ID then his birth certificate, CNI from UK, passport and fee ... only the partner is allowed to go with him inbside the embassy, after that we went to city hall for marriage license it only took 1 or 2days i think .. we just attend to the seminars ... then they give you certificate ... mine is still attach on my marriage contract from city hall even his Singleness certificate