I contacted BSI on 11/5/2020 & got the following response :
Thanks for reaching out. We are closely monitoring the COVID-19 situation and working with the Principality Stadium, as well as the FIM, Welsh Government and Cardiff City Council to review various options for the 2020 Adrian Flux British FIM Speedway Grand Prix. At this stage, preparations for the event are proceeding, however we will adjust our plans as needed to ensure the health and safety of our fans, riders and everyone involved in the event. Thank you for your patience and if & when our plans change, we will be sure to let you know