Freewheeling hubs are used to disengage the front wheels from the front axle/differential/driveshaft, on a selectable 2X/4X vehicle, such a series truck.
Defenders are all-wheel-drive, and as such, do not have freewheeling hubs. Since the transfer case is always turning the front driveshaft/differentail, there would be no advantage to disconnecting the front wheels from the differential, and, in fact, if the front diff was disconnected from the front wheels, all you power would be shifted to the front driveshaft by the center differential (unless put it in locked position) and you would go nowhere, but with class.