hi celtic,
i would say, especially in the uk, if you need any sort of assistance at uni, having a formal diagnosis certainly helps with that. they normally have a specific department that deals with these sort of things, and i have found, where i'm studying anyway, they are generally very helpful.
lecturers and tutors also tend to be more willing to help out and less draconian about attendance, leaving early in the case of a freak out, taking part in things that might cause you problems, etcetera. in addition they should be more accepting of unorthodox working methods and suchlike. at least this has been my experience.
so i would say go for it. from your original post, you sound very similar to myself in terms of "symptoms", and the process of being diagnosed was fairly easy for me.
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?Civil government, so far as it is instituted for the security of property, is in reality instituted for the defense of the rich against the poor, or of those who have some property against those who have none at all.?
Adam Smith