I've had a quick look at the network plan for this S24 season (summer, June-October) for the routes BA expected to operate with the 787-10. I downloaded a plan in early April, and another one the day before yesterday, and there's a large difference between what was expected to be operated with a 78X in April vs May.

• Compared to April's plans BA's May plans see:
  • 28 less return flights operated by 78Xs in June;
  • 31 in July
  • 31 in August
  • 30 in September
  • 52 in October

It's quite clear that BA is seeing at least one 78X less than planned just in April for the whole of the summer, and possibly 2 in October. This is hardly surprising considering that there was one plane expected in March and 2 in May, and here we are with zero.