South African Breweries announced yesterday that Brandes Investment Partners, the San Diego-based asset management group, has taken a  9.12% stake in London listed beer maker. The stake amounts 76.7m shares.   Brandes has been a substantial investor in SAB for several months an indeed, according to SAB director of communications Nick Chaloner, has held close to 9% since last year. The reason for the current announcement was a technical realignment of SAB holdings within the different Brandes companies.