Well if it's in the regs, then it's in black and white....just seems maddnes having a good earth at the DNO cutout, then at the DB end ditching it and then put in earth rod. Again , the University has several of its own substations with massive section boards that feed other large buildings (so technically the substation is the DNO supply) so then there'll be say 3 or 4 300mm2 SWA cables go out to feed other buildings, no separate cpc, then when they enter the building, an earth conductor is took off the armour to an earth bar and then from that you'll have a main protective conductor to the buildings section board, and protective earthing conductors to other services.