The truth wasn’t a defense. Lack of intent to cause sedition wasn’t a defense. Spelling it ‘defence’ wasn’t even a defense.
This was only repealed by section 73 of the Coroners and Justice Act 2009 which, contrary to reasonable expectation, was only passed in 2009.
I simply can’t imagine that in 2008, the UK’s government was prosecuting people for annoying it. I can only imagine the repeal was something they snuck in upon realizing an obsolete embarrassment was still hanging around.
When was the last time someone was convicted of violating it? Who was that person?
(BTW: John Peter Zenger was acquitted. Jury nullification.)