Indeed, a bit sooner than I thought and at the generous end of the scale. Here is the advice:
Originally Posted by British Airways
In view of the recent Coronavirus outbreak in China, guidelines have been published to assist customers travelling on British Airwaysservices to our China gateways.
Advice for British Airways-125 ticketed customers whose BA flight is still OPERATING:
Originally travelling 25 January – 23 February 2020 (but must be ticketed on or before 24 January 2020)
New travel dates: Up to and including ticket validity.
Refunds allowed
Avios bookings included
No re-routing allowed if rebooking.
If you booked via a travel agent, they are the ones to process the booking, I'd leave it a day or two until they get the above advice, which came out at 11:35 hrs today.
The rebooking validity is 355 days from ticketing, with a few complications, but essentially a year to travel.