I went to my regular GP who wrote a note for the public hospital specialist department. He also wrote a note for the private consultant. I'm not used to doctors on the Kowloon/N.T. side so perhaps that's where the extra costs come from ;-)

The note is important for insurance if yours require it. So far in my experience, it was very much necessary otherwise, the costs would not be reimbursed. I get reimbursed for both the private and public system.