In Australia we have a whole host of professionals able to diagnose LDs. For example, Occupational Therapists can do certain testing to aid with writing, language etc. We also have very good educational psychologists trained in the field of children's problems; sometimes you can tap into trainees at the University who are supervised by qualified professionals. I was able to get very good educational physio therapy for my ds this way, as I was willing for the students to 'study' my son, under the watchful supevision of the qualified/mentoring physio.
Just my tuppence worth.