The registration information for your domain is:
Code:
Domain name: partytime-catering.co.uk
...
Registrar:
Namesco Limited t/a Namesco Ltd [Tag = NAMESCO]
URL: http://www.names.co.uk
Relevant dates:
Registered on: 28-Jan-2012
Renewal date: 28-Jan-2014
Last updated: 28-Jan-2012
Registration status:
Registration request being processed.
Name servers:
ns0.phase8.net
ns1.phase8.net
ns2.phase8.net
There seems to be a problem when configuring the nameservers for your domain.
If it just dissapears when you save the record, you should contact your domain provider and ask why you can not save the new nameservers.
From this forum I think we can do nothing more.