The thing is about NICE's argument is since they freely admit that they can't bind medical staff there is no issue with releasing what they believe to be the right guidelines. They have a duty to consult and listen but not to do anything about that, their independence means they can freely publish without regards to the special interest groups. They have kind of undone their own argument pointing at the case law and the underlying law there.
They already understand the objections from the special interests groups, their entire business is predicated on GET and CBT, they are entirely staffed by Psychologists and Physiotherapists and they see their business disappearing in an instant with the release of these guidelines. Given the feedback they have (secretly) received it must be clear the actual objections, there is no reason to drag this out further. NICE does not have to regard itself with the effectiveness of its rollout at all, its not legally required to do so and medical staff are not required to follow their guidance.
Time to take them to court, there is no timeline for release, the client is one of 100s of thousands harmed by the delay who can't get anything done until its released and we can bash our useless doctors over the head with it.