London -Shanghai144 hours -HongKong and HongKong- Hangzhou 144 hours - London

You don't need a visa.
Nice trip.

Thanks for your reply. For the trip London -Shanghai 144 hours- HongKong and HongKong -Hangzhou 144 hours- London. Can I land in Shanghai then take train to Hangzhou for the second part? or I have to land in Hangzhou for 144 hours stay.

Either is fine. You can land in Shanghai and take the train if you want.

Thanks so much for your reply. I have one more question.
For London -Shanghai144 hours -HongKong and HongKong- Hangzhou 144 hours - London, how long do I need to stay in HK to qualify the second part HongKong- Hangzhou 144 hours - London ? I just remember that HK recent strikes/riots, I plan stay there around 4 days, but if anything happens, I might only can stay for 1-2 days, do I still can have the second part HongKong- Hangzhou 144 hours - London?

Chinese immigration have no interest at all in how long you stay in Hong Kong. Even 1 minute is enough. They cease to have any interest in you once you board your flight out of China.