I realise that this is a very specific post but I hope at least some of you will find it useful. I was one of those lucky enough to benefit from Sky's half price deal last Nov/Dec. I have just called them to give my notice to cancel at which point they offered another 6 months half price.
I realise it may have been luck, however the operator stated that she could see that I had received 12 months half price and that they were able to offer another 6 months half price with no further contract commitment if I was willing to stay. This keeps the total at £25.50 including the hd pack for all mixes, movies and sports.
Hopefully this will be useful to someone as previous posts have indicated sky were unwilling to offer anything to customers who had 12 months half price credited to their account.