MacBook Pro (mid 2009) MiniDisplayport to HDTV Cable No Sound

Hi,

I've tried searching the web and various message boards for a solution but I haven't been able to use what I've located.

I have a MacBook Pro (mid 2009) running OS X Mavericks and just purchased a Belkin MacBook Mini DisplayPort to HDTV Cable from my local Apple store. The cable transfers the picture perfectly allowing me to mirror screens and also use my Sony Bravia TV as a second screen but sound isn't transferring as advertised.

I looked at the fixes online which suggested using Preferences > Sound or Audio HDMI but the TV isn't being picked up as an option as an audio output as shown on some of the YouTube tutorials.

Before I trek into town with MacBook in tow I thought I see if anyone here can offer a solution.

Many thanks,

Tom