Mr. Ball's advice is excellent. The 3 courses I speak of take approx. Most teachers welcome questions. My first suggestion would be to discern what type of Montessori school your school is.
Some independent schools remain independent for specific reasons.
Others simply don't meet the standards. Parents should be aware of and comfortable with the school's position and philosophy. Above all, the school has to match your desires and interpretation of Montessori education. Parents know what's right for their child. Every Montessori course I am familiar with are one to two years in length.