Proving the Holocaust happened in a UK libel proceeding required two years and millions of dollars of litigation. https://en.wikipedia.org/wiki/Irving_v_Penguin_Books_Ltd ; a US court would've likely summarily dismissed it on day one.
You'd likely need a lot more than raw text logs in defense.
The case was not about whether the Holocaust happened or not. If you read the link you posted, "Irving claimed to have been libelled on the grounds that Lipstadt had falsely labelled him a Holocaust denier and falsely claimed that he had falsified evidence or deliberately misinterpreted it".
There is no law in England that forbids somebody being a Holocaust denier (unlike in France and Germany). And Nobody was "[p]roving the Holocaust happened in a UK libel proceeding". I have no idea why you keep posting that.
The Irving case was based on him not liking Lipstadt calling him a denier and accusing him as a historian of faking data. Since the court accepted that he was indeed a denier and was using dodgy data, they ruled for Lipstadt.
Now, back to Pretty. The defendants have apologised so I don't see what there is to debate. Dude, the case is over. Let it go.
If you look at the accused, he also owned a UK Scala consultancy that directly competed with Miles Sabin.
His MO seemed to be finding people who would support his public accusations to ruin reputations.
He tried to get me to do it as well. It was weird.