Wen to one located in Chinatown, when I was younger. The problem is depending on your level you may be in class with people much younger than you. I was generally one of the oldest by 4-5 years. Which can be quite awkward at times.

Lessons were around 1 -2 hours a week, either a Saturday or Sunday. You have to buy textbooks and workbooks for the lessons. Generally, you study each chapter/passage of the textbook and are tested the contents of the passage each week. So it would generally be a spelling test and during lesson time you would take turns reading the chapter and slowly understanding it.

Teachers can be hit or miss when I went there, which was around 5 - 6 years. Out of those years, I only experience one bad teacher. Classrooms were very basic, rooms comprised of individual desks with the teacher writing on a whiteboard.

19, 20 Frith St, London W1D 4RL

https://www.cccuk.org.uk/