Hi Hannah,
Unfortunately, you’re going to have to wait until closer to the date of the return flights to see what the options are. If the airline cancels the flight, you’re entitled to a full refund. However, if the flight runs, you’ll need to cancel and take the hit on the administration fees. Your travel insurance may not cover a pandemic, but it’s also worth talking to them if you came home specifically on FCO advice (such as the understanding you would not be able to return home on your anticipated date because of closed borders).
Keep an eye on the FCO recommendations around travel – and also that of Australia, as that’ll affect your rights, too.