@osfan
I would suggest you do nothing until FTTP is actually installed. A good installer will try to work with you to get to the desired ONT location.
They are used to working with poor conduits so if the master socket is your desired location then I'm sure they'd give it a try.
Does the Consumer Unit cupboard have an outside wall? While they will run cable internally it's usually in the same room. They don't go through walls unless pre drilled. What you could do is get a couple of wall plugs and have your drill handy if that's the chosen location. You can do the work while the installer works outside. Note that as it's a new house the corners may have a metal plate to strenthen the corner. Power can the supplied short term via an extension lead until you get someone in.
Brian
