Hi Andy and welcome,

A second, separate, digital tuner (DVB-T2) is required to receive Freeview HD broadcasts.  I'm not sure these were available in March 2009 when this model was released.

Check the features and specifications of your Bravia - I don't think your model has a Freeview HD Tuner.  It has DVB-T (Freeview) and DVB-C (Cable) - but not DVB-T2.

http://www.sony.co.uk/product/TV-80-32-lcd/KDL-32V5500#/TechnicalSpecs

It will display HD content from the HDMI input from a HD box (like Sky HD) or from a DVD/BD HD source.