a) The Twitter link is referencing the Daily Mail. https://www.dailymail.co.uk/news/article-8805697/Furious-bla...
b) The Mail does not source it's claim.
c) All those Excel references in the news seem to postdate (at time of writing) speculation on Excel in IT-heavy forums like this.
While I can believe the Excel conjecture is correct, I wish people would stop referencing it like it's a proven fact, or provide an authoritative source for the Excel claim.
I hate to be that guy, but...