24 Hour transit visa - AKL-CAN-WUH-LHR

I am travelling to London from Auckland, originally only stopping at Guangzhou. However, the airline has just notified me of a change in the flights, which includes an additional flight (Guangzhou to Wuhan) as well as another transit in Wuhan. All in all, its under 24 hours, but I'm not sure this qualifies as the 24hours free transit, as it includes a domestic flight? Travelling with a British passport.
Does anyone know if I would require a visa?

Thanks