CSS is the best school IMHO available worldwide. Highly recommend it.
I thing that doing the course of CSS opened my eyes. I consider my self by far a better rider.
Among many schools in UK , BSS is one of the best.
As found going through the process of selecting a proper school, age, bike type and use and ultimately money are the main factors. Meaning that you have to select the school that most suits you, your bike, your riding style, your needs and ultimately is within your budget.
To sum up any school is a plus for any rider, certainly we pick up a lot depending on skills and instructors but am absolutely certain we improve significantly.