Ok.. so I finally managed to download the newest beta, but not from the cosmos servers. There's a post on the WoW UI Forums
HERE with a bunch of links of people independently hosting the files until the cosmos servers are less bogged down.
I noticed something after I downloaded the update... Thottbot is gone from my Cosmos setup.. wtf!
Was that part of the 'update' that Blizz did was remove the fuctionality of the UI calling external sites within game, forcing Alexander to remove the Thottbot from the UI? If so, that's crap.