Hi Dori,
You could just look at the hostperm.1 file used to
store the blocks on
your profile directory, search for wikipedia or wikimedia with a text
editor, and remove them that way.
Yes, this is the workaround I did in the end. Not all users may be as
"technically savvy" as I though. If wikipedia was not hiding the
complete hostname for which it wished to store a cookie this would not
be a problem.
Kind regards
JG