The special number for this is: 03442 414141
There you can move to Sky Broadband Unlimited Pro, which has ADSL with a static IP address and costs £5 a month more than Sky Broadband Unlimited. This option for non O2/BE migrants appears to be on a "soft" roll out and not mentioned on the website.
If you want a static IP address on fibre, that's also available of course, via Sky Fibre Unlimited Pro. The number for that one is on the Sky Fibre Unlimited sales page.
Edited by Oliver341 (Sat 28-Jun-14 12:33:43)