While I have little truck with the Mail I see absolutely no problem with referring to Wittman as a Nazi.
Being a Haupsturmfuhrer in the SS is a bit of a clue, but being a battalion commander in the LSSAH with such coverage in Signal etc. as a hero of the regime can be seen as some sort of confirmation. He can quite safely be covered in English by the term Nazi or Soldier. In many cases the two are surely allowably interchangable?
Cheers.
Adam

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"Wars cannot be fought with dream stuff" - Sir Percy Hobart.