[eUKhost.com]

You need to add the addon domain as suggested in the tutorial located at http://www.eukhost.com/support/cpanel.php and then you should refer to the thread located at transferring website from 123-reg to eUKhost to know how to change the nameservers of your domain name with 123-reg.

If you wish to transfer your domain name under our registration then you need to change the IPS tags of your domain name from your 123-reg control panel and the tags should be pointed to "ENOM" ( without quotes ). Once you change the tags then you need to inform us and we will accept the domain name under our registration.

If you find it difficult to understand anything out of the tutorials or the thread I mentioned then do let us know and we will guide you further.