Is my new home refurb or new build?

This sounds like a stupid question, but even my potential mortgage lender isn't sure!

I want to buy a house which is part of a development of new build and refurb properties. The property I'm interested in is two houses that have been knocked into one and then completely renovated inside.

I would say this is a refurb, but apparently it may be considered new build, unless I can argue otherwise. Any thoughts on why this might be, or how I can argue the case?