A new documentary on the making of the sound effects editing for DH 2 was released, which can be seen below (with a few new clips from the final battle). Germany's RTL released their making-of special on DH 2, also with new BTS shots of the battle and Gringotts, and new interviews with the cast (unfortunately dubbed in German). Those are here.
(
RTL BTS special on DH 2. )