Transit in China - less than 24 hours

Hi,

I am travelling to Sydney, Australia with a short (3 hour) layover in Canton-Baiyun International Airport in China. I have a UK passport, expiring on 14th June 2018, and a return flight booked on 9th Feb, where I will also have a short layover in China.

Will I be allowed to transit in China? I understand that I do not need a visa as I am in China for less than 24 hours each time, is that correct?

Steph