The Home Office has set up a dedicated web page to help Commonwealth citizens confirm their status in the UK, which can be found here.
There is also a freephone number: 0800 678 1925. This line is open Mon-Sat 9am – 5pm, Sun 10am – 4pm
This is a useful link, letter from Home Office Minister to Caribbean High Commissioners laying out action the government is taking
https://assets.publishing.service.gov.uk/govern ment/uploads/system/uploads/attachment_data/ file/700533/20180416_CN_LA_letter_pdf.pdf