LON - SHA - HKG - LON

I have a client who wishes to travel

LON - SHA (80 hours) - HKG (transit) - LON

A few points to note

1. He travels for business meetings

2. He will be in Shanghai for 80-hours (but I understand this is OK as long as within 72-hour from 0000 the day after arrival)

3. He then flies to Hong Kong (which is a transit) onward back to London

Can you please confirm the client qualifies for visa free travel on this itinerary and for his travel purpose