As you are aware COVID-19 vaccination status is available for people living in England, for international travel, via the NHS App or by calling 119 to request a letter copy. In addition, it is now possible to request a copy of the letter via the NHS website.
People should note that it may take up to five working days to arrive by post. People should wait five working days after they have had their second dose for the system to be updated.
More information is available on the NHS Digital primary care page.