On M+S they have the currently running Disney BOGOF deal. However, they have some DVDs included that aren't elsewhere (Up, Handy Manny, Little Einsteins, Pooh and Tigger movies and more) but most importantly there is also a 10% off code (PERWEBI7) that works BEFORE the BOGOF is added.
Using this and the free delivery to store option you can get certain DVDs for only £3 each (2 for £6).
You should be able to get Up DVD for £6 (its £12 for 2.....if my maths is right!), now thats a BARGAIN.