I figured it was servers for the most part. But no matter how you look at it that is still a large figure. I am more trustworthy of anything on the BBC than any other news service - it's a requirement of their license that they offer unbiased views - so I would love to see the back-up.
But it's a guess that most desktops utilising Linux for home are downloads, so if it accounts for a quarter already in sales alone on the server side - how many desktops truly run Linux - and how many dual boot? We'll probably never get a good answer on this.
And good on the Samaritans, I have a lot of respect for that organization, they always seem to make good decisions based on the requirements of the charity over getting donations.