There's probably not much you can do about the website since all those dates are written by different people or software. I personally tend to use DD-MMM-YYYY format when I write dates manually, mostly because 1) I have an Emacs binding for it and 2) It's less prone to UK/US confusions .

You might have more luck fixing the dates in Pipermail, but I'll warn you that Pipermail is rough code to work with, and hasn't gotten much love in recent years.