Don't believe a word they say!
I signed up with Sky last year for just my TV but 3 months later I decided I would sign up for BB with them. I looked at their website and it said "Existing Customers" would get a £25 voucher if they signed up to other services. I rang Sky and spoke to CS who confirmed that if I go with them for the BB I would get a £25 voucher. I signed up and waited and waited and received nothing!! I rang them up and they said the offer was for new customers. I pointed out that the Advert said "Existing Customers" and sent them a picture of the Ad. A few hours later the Ad disappeared of their website. They would not give me my voucher and insisted that it was for new customers only and virtually called me a liar when I said that their CS has also told me I would get one. So do not believe anything they say to you and get them to send it to you in writing!