pick remaining or available vacancy from uni via clearing process in UCAS. This can only be done if you cannot meet or you give up your firm or insurance choices inUCAS.
e.g. https://digital.ucas.com/coursed ... Engineering&studyYear=2022&destination=Undergraduate&providers=University%20of%20Glasgow&vacancy=int&distanceFromPostcode=1&postcodeDistanceSystem=imperial&pageNumber=1&sort=ProviderAtoZ&clearingPreference=CoursesInClearing