In this case, once you know the result of the original course, you need to apply for visa extension to the head office in London. On the other hand, if you unconditionally apply for a three-year course, you can issue a multiple-entry visa valid for three years. You can return to China or go to other places without re-applying for a visa to enter the UK. If you want to travel to other countries, you still need a visa, and you should consult the embassies and consulates of relevant countries.
China students studying in the UK must apply for an entry visa. If it is funded by a government scholarship, you can apply for an entry visa to embassies and consulates in China, England through relevant institutions; Self-funded students need to apply directly to the British embassy/consulate in charge of visas in their province. Both of them need interviews with embassy/consulate officials. The visa application form can be obtained directly from the visa office of the local British embassy/consulate or downloaded from the website.