I visited the λamda project for two weeks in November 2019.
Lessons were good organized and good material (book, fotocopies, CD etc) was presented. The book was clearly structured and is an official textbook.
Lessons were conducted following the books paragraphs, by free exercises (fotocopies) and by reading/talking the greek language and by grammatical exercises on the board.
Students were grouped according to their level of knowledge and if there is only one student in a given level, the course is not restricted to less hours per day. Every question was answered.
Excursions (Κοινη, Καθαρευουσα, Δημοτικη, αρχαια Ελληνικα, υδωρ<->νερο, οινος<-> κρασι etc) were supported and made it interesting to follow this course.
We would book again a course with the λamda project and we can recommend it to others.