Thanks for the link, it was exactly what i was looking for!
I notice in the nova-t-500 it states -
As of 28/08/2008, according to Michael Krufky, all currently released versions, including the Diversity model, are supported by head of v4l-dvb hg, and the driver is likely to stay ahead of new card releases in the future. Please if anyone finds any of the further comments below still relevant in the next 6 months then mark them so, otherwise I intend to remove them to tidy up.
Is it worth trying to get the TDs working? Or are they rubbish to begin with