A common task we have to perform on behalf of our clients, to do this yourself
1, Signon to your control panel
2, Change your DNS (Nameservers) to that of the host you are transferring to.
3, Update your IPS Tag to that of the transferring company, check here for a full list of Nominet Registrars
4, Acknowledge this via email (if applicable)
4a, Some companies demand a payment to transfer away (uk2) which is not very nice seeing nobody else does.
5, You can now re-register the .co.uk domain.