Her routine has been in place for years. Look at this picture. It was taken several years before the previous picture, yet she has the exact same "Nobody better touch my booze" face. So exactly what and how much does she drink each day?
Elizabeth II actually has a few different favorites Champagne providers. Guess it's good to mix it up every now and then (the brand, not the drinks or the order of them. Those have been in place for years, after all).