Hang on a second before charging headlong in to refund land... Are you saying that Freeview has been updated and that it has caused a compatibility issue with the Bravia? If so, then is the fault a Sony fault, or is it really a problem caused by Freeview that Sony now have to make a patch to fix?
Or to put it another way, if you filled up at a garage and found out the fuel was faulty, would you really go back to the car maker and demand a refund for the cost of the vehicle?
Nearly all hi-tech consumer devices are software driven. It's not uncommon for one manufacturer or organisation to make changes in their software that cause problems in other products. If that is the case, and I realise you're peed off and want the problem fixed, but is demanding a refund the right answer if the problem isn't of the TV manufacturer's making?
One of my customers had a problems with their £800 Denon Blu-ray player freezing. There were also issues with his Sky HD box not working right on certain channels. You wouldn't think the two things were related. It turned out that the Blu-ray issue was a symptom of the problem with the Sky HD box. Fixing the Sky box cured the Blu-Ray. It was because both items are connected via HDMI to the display that one could affect the other. It might be worth you trying a firmware update on the Sky HD box. It can't hurt. Nothing will be deleted. And it might just fix things. Let us know how you get on with it.
Follow the instructions in this
LINK for how to do a Sky HD box firmware update.
As for the store, you haven't given any detail so this is all a bit of conjecture on my part; but if they're stalling about this issue it might be that they've had no official notification from Sony about the problem or a fix. They might be as much in the dark as you.