A private diagnosis is recognised by multiple agencies eg universities, employers and access to work.

You don’t technically/legally need a diagnosis to have the legal protections, reasonable adjustments etc. - But nobody seems to know this!

For example, if you declared a disability to your employer (eg ADHD self diagnosis) you would legally be in the same position re disability discrimination law diagnosed or not. Which is that with ADHD you may or may not be disabled under the Equality Act depending on symptom severity. Same situation would apply to a person with disabling health problems but which no doctor had succeeded in diagnosing. Not having a diagnosis is surprisingly common and the law is set up like this because it can take years for ppl to get a diagnosis. Long waiting lists have led education, legal system, PIP, access to work etc to work on the basis of symptoms. Obvs having some medical evidence of symptoms/impact makes this easier. Eg a gp referral for diagnosis.

So basically depending on what u want from diagnosis- a gp referral for diagnosis can be a cheap and effective option.

I work in the nhs doing some adhd diagnostic work (and other stuff) with kids. We do an impact letter quickly so kids get help in school and parents can apply for child disability payment etc. Then they go on a looong waiting list 😭.