CLEO provides Moodle to over 1,000 schools and 250,000 students in the UK. Each school has its own instance of Moodle that is centrally managed and supported. CLEO offers free training to school staff and has trained over 600 people. Since starting in 2005 with 3 schools, CLEO now provides Moodle to over 400 schools. Upgrades, themes, authentication, enrolment, messaging and file storage present ongoing challenges at CLEO's large scale Moodle implementation.