Megaera down!
After 2 attempts the first night we managed to down the first 4 bosses within 2 hours. We then came back meaning business and one shotted Megaera, with great help from Dawnguard, a willing and very capable tank we pugged.
Photo to follow, missed the screen shot.
Killed 10/06/2013
[NB: This is the image from our second kill]