There are more than a few different ones. I've stumbled across mine in second hand bookshops relatively cheaply.
HMSO London put out a nice booklet 'Vocabulary of German Military Terms and Abbreviations'. I have a copy of the 1942 revision. Not sure if later ones are available.
I also have acopy of a book 'English-German German-English Military Dictionary' by L Von Carstenn published by George G Harrap & Company. I'm not sure when it was first published but I have a copy of the 1941 reprint.
You might be interested in the following downlaodable docuemnt of military abbreviations -
http://downloads.sturmpanzer.net/mlw...reviations.pdf