These guys from the UK offer level 6 testing in Germany and elsewhere:
Cockpit Voices.
They offered me a quick chat on the phone to determine whether level 6 is a realistic option.
This ICAO language stuff makes me want to cry. I had a document from the FAA declaring that I was "English proficient" but the German CAA did not consider the FAA to be competent in this regard and required me to pass the test with a German examiner whose English was ... rather basic.