Problems with BBC iPlayer and Safari

Hi, I'm running OSX Mountain Lion and am trying to play a program on BBC iPlayer using Safari. I can search for a program and click on the link to open its page, but when I do, I can't navigate to the video controls using VoiceOver. I'm using b and shift b to try and find the play button, as well as navigating the screen using the Voiceover cursor, but without any success. Does anyone have any ideas what I might be doing wrong? Thanks, Ed