I also noticed her lack in the breast tissue area, but it seemed okay to others as no one else mentioned it.
At 17-18 years old, maybe she was okay, but with cocaine and other drugs misuse, and not eating properly while on drug binges, her body could not maintain itself in the best possible shape.
Computer-aided photography probably did a lot to fill in the missing inches in her posters and magazine shoots, and it is ironic that only upon coming to I'm a Celebrity that the evidence is now clearer in our eyes.