That's the exact same size that I've gone down from!I was just speaking about this with my husband last night. My boobs kept roughly the same weight until I lost about 2st and the last 1/2 stone seems to have gone from them alone! They are so much smaller but not 'small as such' i've gone from a DD to a C.
It's annoying when I still have a flabby stomach and could do with losing the fat from there, you gotta love our weird and wonderful bodies.