Just an update for anyone reading this thread - at this point in time, the website is still not working and it seems to be an ISP error, but it also seems that connecting to the game through the client is now working.
Unfortunately for users of the WebStart client, not being able to access the site means not being able to access the game for the time being. Hopefully this is being worked on and the site will be accessible sooner rather than later. *crosses fingers*
But for those that use the downloaded version of the client, the game would appear to be accessible, so feel free to log in and start playing again.