I'd cut all cosmetic surgery- unless in the case of major disfigurement (e.g. burns victim) or causes a major issue (you will develop serious scoliosis if your boobs aren't reduced, or a sex change).
I can't find the exact figures, but I know that this won't make too much of a dent, as it's not a major part of the nhs, but even so, we all have a right to health, and getting something cosmetically changed for something very minor ("underdeveloped" breasts) I don't consider health. It's much more important that our surgeons and money are being spent on the really important things like life-changing, or saving, surgery than these trifling matters.
EDIT: I now realize it sounds like I'm saying that a sex change will reduce the chance of scoliosis. I meant that a sex change is a HUGE change to quality of life, while it is cosmetic.