What if a sponsored student has been issued a visa but is unable to travel to the UK?

They will need to inform their Sponsor of the situation so that the absence can be recorded and authorised by the Sponsor. Depending on the length of the delay to being able to enter the UK, you may need to make a fresh application for entry clearance. The Home Office has not provided guidance on whether it will offer refunds in such cases – it is unlikely that it will do so.