UKVI have confirmed that Chinese nationals who cannot return to China will be given an automatic visa extension to 31 March 2020. This applies to any students holding a visa with an expiry date between 24 January 2020 and 30 March 2020, provided they have been compliant with the conditions of the visa prior to the coronavirus outbreak.
Chinese nationals do not need to do anything to get this extension: the new expiry date (31 March 2020) will be added to UK Visas and Immigration's systems. They will be subject to the same immigration conditions as their last visa during the extension period.
If students need a status letter confirming this extension, or a new Biometric Residence Permit with a revised expiry date, they should contact the coronavirus immigration helpline.
Read full guidance from UKVI about student visa extensions.