Cannot get the website www.skymediauk.co.uk/free6 to register my product for an extra 6 months free.

There apears to be an error with the address.
Try this address;
http://www.skymediauk.co.uk/manufacturers_guarantee_registration.php

I hope that helps.

Im trying to register for free 6months but cant get web site it is only coming up with cant register

You need to enter www.skymediauk.co.uk/free6 in address bar not in a search engine. Everything very straightforward after that.