Sky Ultimate On Demand (Sky Box Sets and Netflix) appeared in my account for £0 / nothing / nada / free per month. This is a saving of £8.99 per month if you already subscribe to Netflix.
Only found it as I was checking why my first bill is so high. Might be account specific. Go to My Account then select "view your latest offers".
Forgot to take a picture before signing up but here's one of next month's bill.