The aircraft are due to enter service in October, and will operate to both Hong Kong and Los Angeles on selective flights from London Heathrow.
The tentative dates of entry to service, which can be booked now (and are subject to change) are:
15 October, BA269, Tuesday, Thursday, Saturday
18 October, BA283, Monday, Friday
27 October, BA269, Monday, Wednesday, Thursday, Friday, Sunday
15/16 November, BA25, Monday-Sunday
Here’s a video promoting the new aircraft in the fleet: