Trying to add a Domain which is apparently “inappropriate”

I'm trying to set up a Domain so that a client can receive mail sent to their Domain, but am receiving a "This domain name can't be used because it contains a protected word or inappropriate language...."

I have checked the support page, but it doesn't even broach this subject. It would appear I'm not the first to come across this.

The domain I am trying to create services for is ibbidirect.co.uk. As far as I can tell, there are no inappropriate words contained.

Please can this be escallated, I have a client waiting for this to be set up, and this is not good customer service.