(ShareCast News) - Diageo has appointed Guinness Nigeria as its exclusive distributor of its international premium spirits brands.The FTSE 100 drinks company announced on Monday that Guinness Nigeria, in which Diageo has a 54.3% shareholding, will become the exclusive distributor of its international premium spirits brands from 1 January 2016. In the year ended 30 June 2015, Diageo's international premium spirits net sales in Nigeria were £20m.