Eh Beth,
I did take a look at the study you referenced and find it suspect, since it was subsidized and written by an organization with a clear bias and expectedly, the results of the study support that bias. Therefore, we should no more allow this claim to go unchallenged than we should of any other study conducted by any right or left-leaning organiziton.
So I tried to find statistics that corroborated the study's findings that sexual harrasment has decreased by 46%. As of yet, I've been unable to find any evidence to support that claim. Quite the contrary...this 2006
article shows sexual harrassment in the British military is rife.
There's no causal link established back to the elimination of the British "don't ask and don't tell" in 2000, but the fact that 99% of the women are currently claiming sexual harrasment pretty much destroys the possibility of any improvement since 2000 (unless you intend to claim that prior to 2000, 100% were harrassed).