This article is "the other way around", in that it looks at the situation where people employed are under UK contracts overseas:
https://www.internationalworkplace.com/about-us/news-and-insight/do-you-know-employment-rights-employees-working-abroad
However it does contain one relevant part:
"Depending on where the international assignment is based, it is likely that mandatory local laws will have some effect on the contract, such as mandatory notice periods; working time provisions; local discrimination legislation.
The reverse is also true of workers from abroad working in the UK."
Further, I can find absolutely nothing within the text of the Employment Rights Act 1996 which would exclude Chinese employees in the UK from the provisions of the Act:
https://www.legislation.gov.uk/ukpga/1996/18/contents
So it appears to me that the provisions of the Act DO apply to the staff under you.