CY333.
Which part of britannia 66s post do you not understand? A non native English speaker, to achieve Level 6 English, must take an English test with an Aviation English Language Examiner. It is unlikely that a FE or RT Examiner will hold this qualification ... I don't. I can upgrade a native English speaker to Level 6 (but only a native speaker). Reread the JAA/EASA rules. I presume you covered them for your ATPL exams. Unfortunately not all countries are keeping the rules!
My experience of Aeros is that they are excellent.