Here is the latest on the Silverstone Classic, the end of March early bird deadline has been extended to the end of April:
https://www.silverstoneclassic.com/faqs
"We are closely monitoring the developments relating to the spread of the Coronavirus (COVID-19) and following the updates and advice given by the UK Government, the World Health Organisation and other public bodies. While the latest guidance from the UK Government is to stay at home over the coming weeks, we remain hopeful that the Silverstone Classic will go ahead in four months as planned, although COVID-19 may have some impact on how we run elements of the event. We appreciate that this is an evolving situation, so in the unlikely event that we have to postpone the event from its current scheduled dates, we will determine a date with the Circuit as soon as possible to which we can postpone the event and we will publish details as a matter of priority. All tickets would remain valid. In the meantime, look after yourselves and those around you. We’re all in this together."
'Just so that you know, a '2-4-1 ticket' means 2 tickets for the price of one ticket.