It's going to take better legal expertise than we have to sort out this out, but it looks like one positive outcome of the Monica Leech imbroglio is that the Republic of Ireland now has the "Reynolds defence" available to defendants in libel actions -- thus removing the irony of an Irish Prime Minister having (through an ill-advised libel action) established that defence in English law.
Monica Leech sued the Irish Independent for simply reporting on a mischievous caller to a radio show who had suggested that she had offered favours normally attributed to another Monica in return for government consulting contracts from a particular Minister's department.
She lost the case, but will not get stuck with the costs of both sides (the usual practice in these cases) because the judge ruled that part of the proceedings benefitted the defendant (Irish Times, subs' req'd):
In a ruling earlier in the case, he [the judge] had found there is such a thing as a public interest defence in defamation proceedings. Such a defence could arise where the subject matter of a publication, considered as a whole, was a matter of public interest.
He also ruled there is a professional duty on journalists to seek out information that is of public interest and to impart it responsibly. The steps taken to gather the information must be responsible and fair and a court or jury must have regard to the practical realities of news gathering.
Which is very like the defence that the Sunday Times was allowed to use against Albert Reynolds: a story might be wrong (or at least not provably right) but it is not libelous as long as the publication uses careful methods and the subject is a public figure. There's just a chance that this might open the way for some edgier reporting as the country faces 15 years of the same government.