To some of you people commenting, bringing up the gazette is fine but what is the point of bashing the gazette and saying they suck when we aren't even watching a Gazette video.!
The translation of the katakana is literally : ando.But their official name is &. Because that`s a lil hard to pronounce and to search they translated it into AND. Eccentric agent is not their band name but a sort of trade mark. Therefore they are often called And - eccentric agent- So they do not have a special english name, the Japanese just written the word And in katakana.