what people are very worried about with this particular piece of research is that I’m quite a lot of the people who were part of the study had actually self-reported this condition so they hadn’t necessarily had a formal diagnosis
This is really something that should be strongly emphasized in response: this is an entirely medicine-created problem, where most physicians refuse to diagnose ME/CFS, and most health care systems strongly discourage it. Even though it's mostly misleading because there were additional checks, and that person clearly did not bother to find out.
We should not have this problem, it's entirely a consequence of a profession derelict in its duties with its obsession with psychologizing anything they don't understand, and systems that have failed us at every single opportunity despite being constantly petitioned to do better and shown how bad things are. Once again a problem that we have loudly objected to is being used against us to downplay everything about us.
The truth is that we should have been able to easily find 25K people with clinically diagnosed ME/CFS, there are so many more, this process could have been helped by recruiting and channelling those into the studies, thus ensuring more robust findings. In fact, as far as I know there aren't even 25K people in the UK with a clinical diagnosis of ME/CFS, entirely by choice.
But it did not happen, and the only reason for this is that medicine has failed us miserably, have simply refused to do their job. We did not do this, in fact we have specifically objected to it, and yet again it's being used against us. And because they didn't do their job, we can't have jobs, so while many governments, and especially the UK's, are loudly whining about the high costs of disabled people not being able to work, the only reason why is because THEY didn't do THEIR job. So now they need to do their job so we can regain fulfilling lives.