Manilla - Chengdu (via change at Guangzhou Baiyun airport) - London

With thanks to all those that have previously commented, I would be grateful for advice how to resolve this.

As mentioned, I will be travelling from Manilla - Chengdu, but there is a brief 1.5 hour stop in Baiyan airport (Guangzhou). Given earlier comments, would it be appropriate to apply for the 72 hour free transit on the plane from Baiyun to Chengdu, this would mean I dont have a visa for when I briefly transit through Baiyun from Manilla (which should be OK as no visa required given short stay in airport)?

This would mean my 72 hour free transit is valid from arrival into Chengdu (where I will be spending 72 hrs in the municipality before flying on to London)

Any advice gratefully received :)