UK to Guangzhou (indirect via HK), then fly to HK

I am booking a flight to Guangzhou but the routing means I need to change in HK, where I will wait a couple of hours for the connecting flight. I will then be in Guangzhou for 2 days, and would then fly to HK. Does HK still count as a third country because my original flight started in UK so I can apply for the 72 hour transit visa, or does this not count because I have made a connection via HK?