Scottish soft drinks maker and distributor AG Barr has announced a 15 year franchise extension with energy drink maker, Rockstar.The companies are now tied up until 2024.Barr, the maker of Irn-Bru, is also set to explain to investors at a site visit today more about how it will finance expansion of its Milton Keynes plant.The company says of the £41.5m needed for the project, £15m will come from new debt facilities.BS