It's basically just a database that holds lists of qualified therapists. Therapists pay their annual subsciption fee to go onto the database. Anyone who wants to check if a therapist is qualified can check on there although everyone wont be on there, only those who have subscribed.
Sorry i don't know who their courses are accredited by! Have just had a look on the site and can't find any info. It just says you get a diploma that is accredited!