Unsure
but I believe Air Berlin will not accept people if they failed the DLR.
However I think that's something I saw mentioned but it could be wrong.
I would not waste time though, do what you can to find out more about the DLR. If it's anything like the test I did then it will comprise of logic tests, mental math and others.
Good luck and hope you find a way of getting more study time. You may wish to call in "sick" a few times.