I'd note that the relevant definition of publish isn't the common-sense use (i.e. make available publicly), but merely "the communication of the defamatory matter to a third person" [0]. Indeed the first link in my prior post specifically calls out defamation via private methods of communication (texting) as something that may be actionable.

[0] http://www.hse.gov.uk/enforce/enforcementguide/court/reporti...

It seems like the reform act of 2013 might make these comments in-bounds:

Honest opinion: It is a defence for defamation, to show the statement complained of was a statement of opinion; that it indicated, in general or specific terms, the basis of the opinion; that an honest person could have held the opinion on any fact which existed when the statement was published, including any fact in a privileged statement that was pre-published. The defence is defeated if the claimant shows the defendant did not hold the opinion.