Apologizing for poor journalism is a million leagues away from committing defamation in a legal matrix where malice is required to prove defamation. A very high evidential burden where Trump was always miles short as there never was any.
Issuing court proceedings for the true purpose of suppressing media to discourage this and/or because its product is not to your liking is an improper use of the court and must be struck out as an abuse of process. I think it will be.
Nobody thought the case would take this long as they were acting on recent precedents where the US Networks were sued. They paid out cheaply so their litigation-averse Boards could avoid the wasteful cost of defending what were actually useless claims. They are known as "nuisance payments".
What Brain Cell Trump failed to factor was that the BBC cannot do that. They can only pay out what is all but British taxpayer's money if legal advice supports it. If the case is bogus, as in this case, they must defend.