I've seen a post elsewhere from someone who is known have a source of ITK info:
"People are mistaken if they think JP doesn't want to pull the pin based on any blind loyalty or worry about loss of face. The decision was made a while ago, the Villa game didn't buy Irvine time, it bought the club time. This will be a complete clean sweep job and the club is making sure it's as seamless as possible hence the delay"
In later posts, the same person says that Burton isn't part of this "clean sweep" and the replacement will be "Pulis or Sherwood".
It's a shame that the ITKers on WestBrom.com have fallen silent in terms of posting ITK info, most likely due to the stick they get when they do post, sadly.