Can I travel back to London via HK?

Hi there,

I am looking at the following flight options and wondering if I qualify the 144 hour visa?

London Heathrow > HK 5 nights
HK > Shanghai 2 nights
Shanghai via HK > London Heathrow 1 day

Currently for my return flight back to London I will leave Shanghai and have a 2 hour layover in Hong Kong then catch a flight to London. Is the 144 hour visa permissible in this instance on a US passport?

Many thanks