When I added business cover they asked what I would be doing, when I said occasionly (which it is) moving servers, visits to the datacentres to work on the kit/reconfiguring/rebooting when remote reboots didn't work (what most of the extra driving is), and sometimes carry other staff to meetings and appointment, they said that was fine and wouldn't need commercial driving.
They said that the majority of the work was between fixed premises company premises (a rented rack counts as premises), not visiting clients, so it wasn't commercial driving.