Ed,
Larry is correct that "Anton" was their machine (4U + AH). the BH was Bertha, CH Cäsar, KH Kurfürst, etc, etc. All the reports I have that were made by 1./(F)123 crews use these terms for the aircraft they are flying.
Merry Christmas All,
Melvin
www.aircrewremembrancesociety.co.uk