It is common to study for two master's degrees in Britain. Some people say that we should study in different majors, but this is not the case. The point is that you should give the visa officer a reasonable explanation. You can write a statement telling them that you studied in your previous school first, but you feel that the curriculum and repayment are not as good as the school you want to go to in the future. You want to have a better development in China in the future (for example, because you later found that two master's schools are well-known in China and it is easier to find a good job), so you decided to continue your studies, focusing on the differences between the two courses of the same master's degree and explaining them clearly to the visa officer. You explained it clearly, absolutely no problem.
The visa officer stuck your question because he was afraid that you would want to go to school again and again and want to stay in Britain. As long as your background is all right, your first master's score should not be too low. If you try to get a higher score, they will never stick to you.
In addition, remind LZ that the refusal rate of face-to-face visa is very, very low