I'm not sure about CSC (China Scholarship Concil) funded students, but being an intern funded by a Chinese university myself some years ago, I didn't need to report anything back beyonds a final scientific report signed by my US advisor.
Tangential: in my personal experience, the need for CSC funding for UK PhD programs is due to the very little available funding opportunities for foreign students. Doing a PhD without financial support in an expensive country is ridiculous for most families in China.
Most students would actually try to avoid that if it's possible to secure funding in alternative ways (like the paid PhD programs elsewhere in the world), as CSC funding comes with a requirement of returning to China after finishing the study and this limits opportunities of the students to work abroad afterwards.
Tangential: in my personal experience, the need for CSC funding for UK PhD programs is due to the very little available funding opportunities for foreign students. Doing a PhD without financial support in an expensive country is ridiculous for most families in China.
Most students would actually try to avoid that if it's possible to secure funding in alternative ways (like the paid PhD programs elsewhere in the world), as CSC funding comes with a requirement of returning to China after finishing the study and this limits opportunities of the students to work abroad afterwards.