UK law states that electrical items should be good for 5 years regardless of whatever warranty the manufacturesr give.
I used to indtall tv's for a livng a few years ago and all it takes is a card with the updated software, in fact it can also be done over the ariel on most models.
Not sure on that particular problem but I know for a fact a lot of issue were with Sharp and Samsung, those two being one of the worst for having to update via card, Panasonic on the other hand were easy and it used to be done over the air so we could do it without the need for an engineers card.
But as I say, get back in touch and demand they sort it out mate. After all it is their fault which has caused this issue and if they acknowledge this then tell them to sort it or you will be going public along with seeking legal advice.