Yes, You can just register the domain name and get a hosting service at a later stage.

When you wish to add the hosting or email & web forwarding service to your domain you can do so at the following link: https://www.pickaweb.co.uk/billing/order/orderwiz.php
 
Because you already have a domain name that you wish to use, please select the option: “I already have a domain name which I wish to use for the service. I will change the name servers”.
 
Please also register as an existing customer using your login details which were sent to you when you placed your order initially. If you do not have these details then you can use the forgotten password feature at the following link & they will be emailed to you: https://www.pickaweb.co.uk/billing