We already have 3 phase electricity coming into the house.
Ah. I know nothing about 3-phase or commercial supplies, but fitting an isolator next to the consumer unit is pretty standard these days I would have thought. It enables all work to be done by domestic electricians to be done perfectly safely rather than than in the old days when they either had to get the DNO in to switch off or wiggle the fuse link out themselves without breaking that little lead seal they put in to stop you doing it.
