Apart from the motivation issue (Glenn has no motivation to lie, while Peters/Henry have plenty) of who is telling the truth, there is also the timing issue. Glenn has not just suddenly stated that Peters solicited the money. He told the PM this back in February. Peters denied it, and denied a donation, and the donation was later established to be correct.
The fact of the donation has been established. Owen Glenn has stated Peters solicted it, and thanked him for it. And it is almost beyond belief that you would donate $100,000 to help someone and not tell them about it. Especially if you are Owen Glenn!
Now Peters and Henry have their story that Winston knew nothing (despite even Helen telling him about it) and that Henry heard from someone else to contact Glenn. Well Henry now has to substantiate his version of events. Was that “other person” Roger McClay or a member of Winston’s staff? If so, guess who told them about it! Does he have a copy of phone records or e-mails to show he contacted Glenn and solicited the money himself? Or will the e-mail just show he sent through bank account details?