The title "Sir or Dame" only applies to those knight/dame hoods awarded by the British monarch (in most cases). There are numerous knight/dame hoods awarded by other than the British monarch and they (again, in most cases) will come with the language equivalent of knight - German=Ritter, French=Chevalier/Dame, Italian=Cavaliere, Danish=Ridder/Dame, Spanish=Caballero/Dama, Republic of Georgia=Raindi, Portugese=Cavaleiro, Russian=Vityaz'. Chev. (for Chevalier) is used more frequently than any other.
This is the simple explanation as there are several ranks of Knighthood within the various Orders and also several grades of Knighthood. All Knighthoods do not "enoble" the recipient and some are only valid while a member of the Order, some are for life and some are hereditary
Admiral is not actually a "title" in this sense as it is a military (naval) rank but it would still be listed in the Prefix Box.