Are you willing to foot the legal bills?
The odds of a successful libel claim are nonexistent if eight independent journalistic organizations have reported something as a fact. Libel's just about impossible to prove anyway, and it definitely wouldn't apply here. For one thing, truthfulness is always a defense to libel "The Guardian reported .... " is certainly a fact.
Note also, if this were legitimate libel the place to start would be the deep pockets of the media organizations that are STILL publishing the statements about Mr. DI Stefano on their website.
That said, BLP isn't just about protecting us from legal disputes, it's also about making sure we do the right thing and accurately portray Di Stefano, regardless of whether we could ever get into problems for it.
So, my "Probably no legal concerns here" aside, I'm certainly not the foundations laywers, so as I said on the article talk page-- no hurry at all. It's a minefield, go nice and slow, letting the laywers and foundation take the lead. It'll all come out in the wash.
Alec