Log into your Sky account and then look at Sky Products and you will see it there click on it and claim.
"Our Sky Wireless Booster extends the wi-fi signal to help you get online in an area of the home you may not have been able to before.
It's designed to work best with the Sky Hub and other Sky Wireless 'N' routers. If you don't have either, we recommend upgrading to the Sky Hub first, as this uses our most up-to-date technology to provide a great wireless range.
Your home environment may affect the range of your wi-fi signal."
"Free for new and existing Sky Broadband customers: Subject to availability by claiming online after broadband activation (before 30.1.14). One per household."
I was part of the test team for this product about 4 months ago
It's worth getting. I saw a bit of an improvement in terms of accessing wi-fi at home.