look here
Apparently the group have past history for giving the money off and then taking it back months down the line when it's too late to do anything about it.
There's now apparently a £50 off a £50 spend code. How can that be anything but a scam on littlewoods part? They want people to spend more than they intended, but they never intend to honour the code.
I've used a couple of these codes myself, but I'm thinking of returning the stuff as it looks like a total scam to me.