In the old jungle movies, the hero was always the 'great white hunter'. The locals always referred to them as 'Big Bwana'. I guess in my circle of friends this translated to 'Big Banana', and this, merged with 'anagrammer', gives us BIG BANANAGRAMMER or, 'What a hero! Fancy being able to solve anagrams like that! Tops!'
Okay, so it's silly - but I thought it sounded good. (But you do have to give it the American pronunciation of 'banana').