You have to specifically ask to be ex-directory. By default you are in the phone book, which is public information. Go to Customer Support / Directories / 1081 Directory Inquiries and look yourself up. If your name is there then it is public information. If you don't want that then you have to request PCCW to be ex-directory.
But since you current number has been in a public directory which may exist for a while you may want to change your number at the same time.