Just found an offer on Topcashback for a months free trial of Now TV's Sky movies with cashback of £10.10. Not sure if you'd only get this payment if you signed up for a paid month after the trial but at worst you've got the first two months either free or paid for with the cashback! Great for films over the christmas period.
*Apparently. there is a similar offer already on here but this doesn't include the free trial*