4OD works fine and is easier to navigate through their Mobile site, as does BBC and ITV, from their websites. Channel 5 is tricky as they use Flash 11. Channel 5 seems to work via the new Preview option on Youtube.
You could use a VPN or a service such as "Tunlr". I suggest the following thread for explanations, ideas, instructional video, etc.: http://www.googletvforum.org/forum/vizio-co-star/6630-vpn-options-vizio-co-star.html
Cheers. I cleared my Cache and it worked fine this time @ 720P. I think it might have got stuck at the 2nd ad break. In other words, it broke for the ad and didn't start the ad or anything. I just got the spinning wheel.