There were 3 achievements I got that day, Heroic: Fall of the Lich King, Neck-Deep in Vile and Bane of the Fallen King. Only 2 showed, and the guild achievement didn't show on my screen either.
Anyway, the strategy we used was so different to how you are supposed to do it (essentially it was a burn!) and we spent so many times wiping trying to do it, we had to pull in a few extras to make that little bit of difference.
So our successful burn strategy was to stand in the original positions, make sure you move out of that black flare thing on the ground that blows up and knocks you off, and didn't bother dispelling the disease. At least healing through Infest was easy. Then once we hit the ice phase, the ranged stood in the ice and DPS'd LK and the orbs, and the melee came out and DPSd the spirits. Basically it went so quick that it transitioned straight back into another ice then into the spirits phase. The first time that happened we didn't know that happened that it went like this:
"OK ice phase is finished, everyone back in."
"No wait, it's another ice phase, everyone back out!"
"I think it's going straight into the next phase..."
"Shit shit everyone back in!"
"Oh crap, I just got out here and the ice fell off..."
"You told me to step out here!"
"OMG I didn't know it was going to do that."
"We got this, we got this!"
So the next go we had it. That was cool! I ended up with Valius, Gavel of the Lightbringer to play with, so I have to think how I'd use that in a transmog. A blue set! Just what I need :D Thanks to Aza for organising the run, it was awesome!