The Trent 1000 engine issues are now very well understood by both Rolls-Royce and BA. While the extra inspections mean that the aircraft may not be scheduled to fly quite as much as other types, I don’t think you should be worrying about a higher likelihood of short-notice flight cancellations (particularly as you are planning to travel next year). The affected engines are progressively being fitted with upgraded parts. I am booked to fly NRT-LHR in a couple of weeks so hopefully I won’t be forced to eat my words!