"Something about my installations of Abrowser and Icecat is over-riding the
blocked status of those domains. What could that be ?"
It's nothing to do with the browser. At all. The determination of which HTTP
response code to sent (either "200 OK" along with the requested resource or
to instead serve "403 Forbidden" is entirely the decision of the web server.
Entirely.
It'll be almost impossible for us to determine exactly what it wrong without
in-depth access to the full (and I mean full) web server configuration. Since
you mention cPanel (a proprietary program.... eek!) you will probably want to
get in touch with your hosting company to discuss the problem in more detail.
Sorry, but this is not a Trisquel problem.
