I think it's a good idea for everyone to be on the same page as to what is meant by the PT.
Here's a link:
http://www.theperrinclinic.com/about.html From Perrin's website.
It also discusses diagnosing ME and treating ME.
For me, looking at the page that comes from the man himself my first biggest problem is that the diagnostic process for ME is not shared. I expect this is because the way of doing that is to protect the technique from use by anyone. This means that even if you pay for treatment you will likely not be told what the process is being used on you or how it works--another issue since it may be the case that a theory has been cobbled together for the sake of credibility but the creators of these techniques may not in fact know why something works if/when it does.
A couple of other points to make. With these therapies it is always an issue that some practitioners are better than others. So who you see matters even if the therapy does have some efficacy.
And if the therapies do in fact help IMO I don't see that they can claim to cure and also if there is benefit it lasts only so long as therapy is continued. Once finished the benefit diminishes until the prior baseline is the norm.
And when they claim benefits for ME it is rather highly likely they are talking about a subset because as we know we all experience some core symptoms and then a variety of dissimilar symptoms. It seems possible to me that some people with very specific neuro symptoms may be somewhat helped by manual therapies that work to relax the nervous system--temporarily. Just IMO.