Gary Brookers nickname?
Known to fans and fellow-musicians as ‘The Commander’ but BtP sometimes uses ‘El Gubernator’ because of the Latin words for ‘A Salty Dog’ which you can see at http://www.procolharum.com/salty_latin.htm ; more about nicknames at http://www.procolharum.com/cucumber.htm You’re not thinking of ‘Gazza’ … this is not a proper nickname, although he does call his Record Label ‘Gazza’ : see http://www.procolharum.com/gazza.
