Thanks for your review @Bootie. I also have the book (there's a chain of arts/remaindered bookshops called The Works in England - they usually have lots of cheap military books), so I picked it up for about three quid. I agree about the gruesome "Sven Hassel" quality - we seem to have had a similar teenage . Some of it is so horrible that I wouldn't recommend it to anyone of a sensitive nature.
I found it mostly interesting, especially as a German POV of the Eastern Front. One thing I should mention, it says in the introduction that "Sepp Allerberger" is a pseudonym to keep his real identity quiet, so that's why you can't find him on a list of Knights Cross recipients. Of course the guy might be a fantasist and liar, difficult to tell.
It has been translated from German... in the original German book a pseudonym Franz Karner was used but for the British print his real name Josef Sepp Allerberger was inserted but the introduction stating it was a pseudonym was not changed.
I looked him up on the list of Kts Cross holders: you are right, he's not there. I must say this makes me tend to agree with you - if he's lied about something so important then it seems reasonable to assume that a lot of what he said is BS.
The thing that always sticks out is that individual German tanks or soldiers kill hundreds and hundreds of their enemies, lose a man or two heroically, and still manage to lose battles and the war. It is as if they are fighting ants and not other human beings.