I need clarification please, I’m travelling through bringing en route from New Zealand to London

No, you don't. Your itinerary will be covered by 24 hour visa free transit and you do not need any kind of visa. In vase if you want to exit the airport, regardless of the fact that the layover is not ideally long, you can apply for a temporary entry permit at 24/144 transit counter where you will present your flight tickets and tell that you would like to enjoy Beijing for couple of hours rather than staying at the airport. If you remain at the airport, you will stay airside and you do not have to perform any formalities. You will not be a subject of immigration or customs check, but you will just walk from one to the other flight. Basically, you have nothing to be worried about. Have a nice journey.