There are two options available when considering using a new domain name on your hosting account, and both options incur a £5 administration charge:
1. Rename the existing hosting package
We can rename your hosting package. Your files remain on the server, but your hosting becomes associated with the new domain name. Prior to commencing this procedure we recommend you back-up all files. Depending on how your site is programmed you may still need to republish and modify pages on your site for them to work with the new domain.
2. Deletion of original package and creation of a new one
We can delete your original hosting package and create a new one for the new domain name. Your files are all deleted so you would need to republish your files to the server.
Other options are available for using one hosting account with multiple domains. Please refer to the following article HERE