Am I eligible for 72 hours visa free transit?

Hi,

I am a British Citizen passport holder and I’m planning a visit to Hong Kong and China.

Plan A
London to Hong Kong 6 days
Hong Kong to Beijing 3 days
Beijing to London (return home)

Plan B
London to Beijing 3 days
Beijing to Hong Kong 6 days
Hong Kong to London (return home)

Am I eligible for visa free in Beijing for Plan A and Plan B?

Thank you