Dear Mr. Richard Rimmer,
Thank you for your question.
We would like to inform that The UK passport holders are granted a visa-exempt stay of 15 days with single entry. Their arrival date must not be within 30 days from their last exit date with visa exemption. Otherwise, they will need a Vietnam visa.
Should you have any further inquiries, please do not hesitate to contact us at firstname.lastname@example.org or call us at (+84) 909 343 525
Hannah Yan (Ms.)