https://www.gov.uk/guidance/coronavirus ... rom-the-uk
Subject to the below guidance, most people in the UK whose immigration status is affected by the coronavirus outbreak will get an automatic extension of their visa until 31 March 2020.
Chinese nationals in the UK whose visa has recently expired or is about to expire
You don’t need to do anything to get this extension.
You will remain subject to the same immigration conditions attached to your visa during the extension period.
You will not automatically receive a new visa or Biometric Residence Permit card.
Your new expiry date (31 March 2020) will be added to UK Visas and Immigration’s systems.