Appreciate it's a long shot, but some family members are on QF1 from SIN to LHR today/yesterday (2nd March) - they were originally scheduled to fly to LHR with Emirates on Saturday but had things cancelled for obvious reasons, and they managed to snap up the last 2 seats on QF1 within the last 24 hours.

According to FR24 it looks like the a/c needed to return to the gate from the holding point. I can't seem to get hold of anyone to verify, but if anyone who can verify what the score is with that flight, it would be appreciated - QF customer service is just quoting the publicly-available data at me ...

https://www.flightradar24.com/data/flights/qf1#3e90a243

Edit - looks like the flight has left, all good