No, other research outputs are still eligible for REF submission, but the open access policy for REF2021 currently only covers journal articles and conference proceedings. It is expected that open access will be required for a wider range of outputs in future exercises.
Under Brunel’s Research Integrity Code, researchers are encouraged to make all output types open access, wherever possible. Open access to a range of research outputs also contributes to a robust and vital research environment. It is also increasingly required and encouraged by many research funders, including UK Research & Innovation, Wellcome Trust, and the European Commission.