[eluser]kurucu[/eluser]
It sounds like you have merged two items: (legal) business and offices.
I would have a businesses table, with registered name, VAT number etc and then a separate offices table, which lists only address information.
Then you have one business entry, and several offices entries including your head office linked to that business. If required, you could mark one as the head office with a flag. Perhaps instead of head office, you would flag registered office, so that you know that address is the one where the business is legally registered.
It's not far off what you suggested, but tries to clearly define and normalise the relationship.