Hi £25 a month is the 10Mb package I presume. It has actually dropped to £20 Per month. I get it for £16 per month....If you are out of contract (Over 12months), which you will be if you signed up with NTL (as I did), then phone retentions (150 from VM phone or 0800 298 5770 )and tell them that Sky are offering you a better deal.....See what they will discount you to. I do this every year at the end of each discount. You also get £1 off for going paperless on your bill.
Give it a go...What have you to lose....Don't be wishy washy though....and be very nice.