Hmmm...you've pointed me in the right direction, perhaps, caper. FF and IE don't see me as logged in, but Opera does [still...]. So it could be a cookie failure in Opera.
... and so it was. One was stuck, retaining the login after I "logged out"; CCleaner wasn't removing it, either... I don't know why not. But a more direct approach worked.
What's happening is that the Opera cookie file was poppping in two places [the default folder and its parent folder], both files a bit different in content. I deleted both files, problem solved.
At the moment it is not using the default location, only its parent folder.. I guess that's why CCleaner was missing one file before. But why Opera was writing to the "extra" file and then not letting an instruction from Daniweb remove an entry I don't know.
I deleted the cookie file again, and upon opening Opera it again builds only in the parent location; CCleaner deals with it correctly now, also??!! .
I'll drop them a word at Opera... they're hot on stuff like that.