Just been in the Glasgow Braehead Sainsburys this afternoon and they had a decent selection of blu-rays on sale. Most of them were £9 including Iron Man, I am Legend, 300, Rock'n'Rolla, Kung Fu Panda and many more i cant recall now, they also had Wall E for £7, High School Musical 3 for £5. Harry Potter years 1 to 4 were only £5 each and year 5 Order Of The Phoenix was a mere £3. I know from personal experience that a lot of Sainsburys deals can be store specific so i highly recommend you call your local store first to check before heading off on a wild goose chase.
Blu-ray clearance Instore Sainsburys incl. Harry Potter and the Order of the Phoenix £3 plus loads more