Whereas a tank in a Victorian setting isn't an anachronism at all. 
It would seem accuracy in linguistics is as illusive... ;->=
That said, there's no need to argue; English steals from EVERYBODY. If there were an L'académie Anglaise, it would be spelled just like that, and would consist of folks sitting around cataloging changes that can't be stopped.
My favorite example is stealing the same word twice from French, just waiting long enough for the French to change the pronounciation...
Speaking of French, how about calling it 'La Bête Noire' , as the crews love hearing it on the lips of the French opposition?
Oh, that would be me not giving up again...
Doug