That's the same as the movie deal Asda had on their pizzas a few months ago (though was £5 spend at Asda), the claim process was the same as that describes with go to one site by date X, get an email with a code, then go to the other site by date Y, but was rubbish, didn't work. I had to get medieval with Asda to get them to honour it, they just tried to palm me off with "sorry, third party promo, nothing to do with us guv". And then the film choice was rubbish, there was hardly anything from the last 10 years that you could watch for £5.49, for nearly everything that's not on Freeview every other week you had to top up the £5.49 credit with more cash.
As for sparks mine says "you have used all your sparks offers" (huh? when?) and is giving me nothing at all now