I have done a 10 weeks beginners course on Thai in the Cactus Language school in Holborn. I am quite happy with the experience. The venue was very nice and the group size was appropriate. The staff was quick to reply to any queries that I had. The teacher was very helpful and she adapted to the to the learning pace of the group. In some lessons we would learn a lot and in the others we would consolidate that learning and practice. The focus was always on speaking/hearing and we really developed those areas. I couldn't speak any Thai before and now I am able to have some (albeit very limited) conversations with Thai people. I am really happy with the course and I totally recommend it!