IMO not worth much as domains on their own, as you say these are brandable domains that you would have to build a website around to add value. 'New Designs' would be worth something, the singular 'New Design' even more so, less words are generally worth more, in terms of value.
What kind of website would you envisage these being used for? Promoting new phones/appliances/clothing or maybe for a web/graphic design company? Its all about how you would monetise a website, that in turn adds value to the domains.
Edit: Looking at the the singular brandnewdesign//com, co.uk & net, they all seem to be in use, may make it harder to build a brand on the plural.