If your leave expires between 24th Jan 2020 and 31st May 2020 and you cannot leave because of coronavirus travel restrictions or self-isolation, your visa will be extended to 31st May 2020.
The Home Office has also set up a Coronavirus Immigration Help Centre, which may be able to offer more advice.
Phone: 0800 678 1767 (Monday to Friday, 9am to 5pm)
Here’s the full advice from the Home Office: https://www.gov.uk/guidance/coronavirus-covid-19-advice-for-uk-visa-applicants-and-temporary-uk-residents
If you have any further queries or want to raise an individual case, please don’t hesitate to get in touch with me at firstname.lastname@example.org.