Cannot turn iTunes Match on
So I navigated to the iTunes Match page on the Apple website and clicked the big subscribe button. I remember going through all the details and I've been charged, but the iTunes match menu option on the left menu-bar in iTunes has not appeared. Clicking Store>Turn on iTunes Match does absolutely nothing, just hangs. I've tried signing out of the store, clearing the store cache, shutting down iTunes, cold booting, and trying again to no avail. I've also reinstalled iTunes to no avail, and if I re-navigate to the subscribe button on the website it launches iTunes, goes the the iTunes Match store page and at the bottom where there'd normally be a 'Subscribe' button there is a 'Done' button - If i click this iTunes reloads the store home page and does absolutely nothing. Genius still works, iCloud is definitely setup and working on my Mac, I've tried multiple internet connections in case it was a firewall issue, etc etc
If it helps I'm running the latest release of Lion, and iTunes is completely up to date. Interestingly I have the option to turn on iTunes Match on my iPhone, but obviously I cannot sync any music as nothing has been matched/uploaded.
MacBook Air (13-inch Late 2010), iOS 5.0.1