According to SS, Suzie Toase, who played Death Eater Alecto Carrow in Half-Blood Prince, confirmed that she would be back for Deathly Hallows.

We’re seeing a lot of you at the moment, not least in Harry Potter. Do you feel like you’re now moving to the next level in your career?
I certainly hope that I am. I didn’t do that much in the last Harry Potter film, so it didn’t change my career all that dramatically, but I’m in the next one as well so we’ll see if that has any impact.